L-14-245, Response to Request for Additional Information Regarding Request for Licensing Action on Alternative Accident Source Term Radiological Dose Calculations: Difference between revisions
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:I i5 Document Numberfrdle Edition, Date ~ 6 Piping 38 PNPP drawing Ss-304-661, Sheet 105.2, Piping Isometric-Containment Spray RevisionC 0 181 0 System 39 PNPP Drawing D-314-661, Sheet 7, Containment Vessel Spray Ring "D" RevisionB 0 181 0 40 PNPP Drawing SS-304-661, Sheet 102.2, Piping Isometric-Containment RevlsionB 0 *181 D Spray System Reactor Building 41 PNPP Drawing D-314-661, Sheet 6, Containment Vessel Spray Ring "F" Revision B D 181 0 42 PSAT 04202H.08, Steamline: Particulate Decontamination Calculation. Revision 1 D 181 0 43 PSAT 04212H.02, Drywell Sweep-Out Rate and Related Thermal-Hydraulic Revision 1 181 D 0 Conditions Inside Containment 44 NUREG-0800, Standard Review Plan, 15.6.5, Appendix B, Radiological Revision 1, 181 D 0 Consequences of a Design Basis L~f-COOlant Accident: Leakage from July 1981 Engineered Safety Feature Components Outside Containment 45 PNPP Drawing 511-0016-00000, Reactor Building - Steel Framing Sections Revision O D 181 0 and Details 46 CEI Calculation 3.2.6.3, LOCA Doses as a Fundlon of Spray Initiation lime Revision 0 181 0 0 I 47 003.008-001-00, FSAR Figure 3.8-1, "Typical Section of Reador Building Revision 12 181 0 0 Complex." | :I i5 Document Numberfrdle Edition, Date ~ 6 Piping 38 PNPP drawing Ss-304-661, Sheet 105.2, Piping Isometric-Containment Spray RevisionC 0 181 0 System 39 PNPP Drawing D-314-661, Sheet 7, Containment Vessel Spray Ring "D" RevisionB 0 181 0 40 PNPP Drawing SS-304-661, Sheet 102.2, Piping Isometric-Containment RevlsionB 0 *181 D Spray System Reactor Building 41 PNPP Drawing D-314-661, Sheet 6, Containment Vessel Spray Ring "F" Revision B D 181 0 42 PSAT 04202H.08, Steamline: Particulate Decontamination Calculation. Revision 1 D 181 0 43 PSAT 04212H.02, Drywell Sweep-Out Rate and Related Thermal-Hydraulic Revision 1 181 D 0 Conditions Inside Containment 44 NUREG-0800, Standard Review Plan, 15.6.5, Appendix B, Radiological Revision 1, 181 D 0 Consequences of a Design Basis L~f-COOlant Accident: Leakage from July 1981 Engineered Safety Feature Components Outside Containment 45 PNPP Drawing 511-0016-00000, Reactor Building - Steel Framing Sections Revision O D 181 0 and Details 46 CEI Calculation 3.2.6.3, LOCA Doses as a Fundlon of Spray Initiation lime Revision 0 181 0 0 I 47 003.008-001-00, FSAR Figure 3.8-1, "Typical Section of Reador Building Revision 12 181 0 0 Complex." | ||
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: 6. 71 cfm (24-24.5 hrs) 2 - Control Room Intake . | : 6. 71 cfm (24-24.5 hrs) 2 - Control Room Intake . | ||
6000 cfm + 10% = 6600 cfm 1375 cfm after CRERS initiation 3 - Control Room Exhaust 4800cfm 1375 cfm after CRERS initiation CONTROL ROOM - 3 390,020tt3 | 6000 cfm + 10% = 6600 cfm 1375 cfm after CRERS initiation 3 - Control Room Exhaust 4800cfm 1375 cfm after CRERS initiation CONTROL ROOM - 3 390,020tt3 | ||
Page 35 Figure 2 Fission Product Transport Model (MSIV and Containment Leakage Pathways) | Page 35 Figure 2 Fission Product Transport Model (MSIV and Containment Leakage Pathways) | ||
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D D D D D D | D D D D D D | ||
Latest revision as of 13:54, 25 February 2020
ML14203A625 | |
Person / Time | |
---|---|
Site: | Perry ![]() |
Issue date: | 07/22/2014 |
From: | Harkness E FirstEnergy Nuclear Operating Co |
To: | Document Control Desk, Office of Nuclear Reactor Regulation |
References | |
L-14-245, TAC MF3197 | |
Download: ML14203A625 (93) | |
Text
FENOC' Perry Nuclear Power Plant P.O. Box97 10 Center Road RrstEnergy Nuclear Operating Company Perry. Ohio 44081 Em8st J. Harkness 440-280-5382 Vice President Fax: 440-280-8029 July 22, 2014 L--*14-245 10 CFR 50.90 ATTN: Document Control Desk U.S. Nuclear Regulatory Commission Washington, DC 20555-0001
SUBJECT:
Perry Nuclear Power Plant Docket No. 50-440, License No. NPF-58 Response to Request for Additional Information Regarding Request for Licensing Action on Alternative Accident Source Term Radiological Dose Calculations (TAC No. MF3197)
A request for licensing action regarding alternative accident source term radiological dose calculations was submitted to the Nuclear Regulatory Commission (NRC) by letter dated December 6, 2013 (Accession No. ML13343A013). The NRC staff requested additional information in a letter dated June 24, 2014 (Accession No. ML14162A409).
The requested information is provided in Attachment 1. In addition, the effects of several necessary changes to the supporting dose calculations are presented in Attachment 2.
No changes were identified to the previously provided Significant Hazards Consideration.
There are no regulatory commitments contained in this submittal. If there are any questions or if additional information is required, please contact Mr. Thomas A. Lentz, Manager- Fleet Licensing, at 330-315-6810.
I declare under penalty of perjury that the foregoing is true and correct. Executed on July 2Z. , 2014.
Sincerely, Ernest J. Harkness Attachments:
- 1. Response to Request for Additional Information on Radiological Dose Calculations
- 2. Effects of Necessary Changes to Supporting Radiological Dose Calculations cc: NRC Region Ill Administrator NRC Resident Inspector NRC Project Manager State of Ohio (NRC Liaison)
Utility Radiological Safety Board
"\'.,
Attachment 1 L-14-245 Response to Request for Additional Information on Radiological Dose Calculations Page 1 of 16 FirstEnergy Nuclear Operating Company (FENOC) provided a request for licensing action (RLA) regarding alternative accident source term radiological dose calculations to the Nuclear Regulatory Commission (NRC) in a letter dated December 6, 2013. The NRC staff requested additional information in a letter dated June 24, 2014 .. The requested information is identified using bold text, followed by the FENOC response.
- 1. For those changes to the current licensing basis (CLB) parameters used in the affected dose consequence analyses, provide additional Information describing for each affected design basis accident, all the basic parameters used in the dose consequence analyses. For each parameter, please indicate the CLB .
value, the revised value where applicable, and the basis for any. changes made to the CLB values. The U.S. Nuclear Regulatory Commission (NRC) staff requests that this information be presented in separate tables for each accident evaluated.
Response: A matrix is provided for the loss of coolant accident (LOCA), the control rod drop accident (CRDA) scenarios, and the main steam line break outside containment (MSLBOC) analyses.
LOCA Current Licensing Basis Proposed Licensing Parameter Basis for changes
[Existing location] Basis
[Proposed location]
Core Source Term General Electric (GE)12/ Global Nuclear GNF2 fuel design to Basis GE14 Fuel (GNF)2 be introduced at PNPP during next
[GE12= Amendment 112 [Updated Safety Analysis fuel cycle (power uprate), Report (USAR)
NRC Safety Evaluation pg. 15.6-65]
(SE) pg. 4; GE14= 10 CFR 50.59 review when converted from GE12]
Power Level 102% of rated thermal 102% of rated thermal No change power = 3758 megawatts =
power 3833 MWt (existing LOCA thermal (MWt) x 1.02 = [USAR pg. 15.6-24 & dose calculation in 3833 MWt 15.6-58 thru 60] support of
[Amendment 112; NRC SE Amendment 112 did pg. 45] assume 3833 MWt although several USAR pages simply reflect the licensed 100% RTP value of 3758 MWt)
Attachment 1 L-14-245 Page 2of16 Isotopes in source 76 isotopes 6a isotopes Based on isotopes term [Calculations supporting [Request for licensing used in the Amendment 1a3 (the action (RLA} submittal RADTRAD PNPP pilot plant AST dated 12/6/2a13, and computer code amendment}] Amendment TBD dated TBD]
Dose Conversion Federal Guidance Report FGR 11and12 Use of Regulatory Factors (FGR) 11 [USAR pg. 15.a-37) Guide (RG} 1.183,
[USAR pg. 15.a-37) Section 4.1.2 and 4.1.4.
Gap Release 3a seconds 2 minutes (BWR) Per RG 1.183, Timing [This assumption was not [USAR pg. 15.6-22 is Table4; specified in the USAR but revised to reference BWR-specific was assumed in the RG 1.183 for timing of the calculations supporting releases, and Table 4 of Amendment 1a3] RG 1.183 specifies 2 minutes for onset of BWR gap release]
Credit for decay Not considered Decay considered Utility decision since during 2 minutes RG 1.183 does not
[USAR pg. 15.6-23) before start of the specify this gap release.
Suppression Pool No Credit No Credit No change Scrubbing
[USAR 15.6-27) [USAR 15.6-27)
Drywell Volume 2. 765x1 as feet (ft} 3 2. 765x1 as ft 3 No change
[USAR pg. 15.6-58] [USAR pg. 15.6-58)
Containment 1.1654x1 as ft 3 1.1654x106 ft 3 No change Volume (excluding [USAR pg. 6.5-56 & [USAR pg. 6.5-56 & (Note: Table 6.5-9 &
drywell} 15.6-58) 15.6-58) Table 15.6-12a markups are correcting typos)
Volume of Sprayed 4.81x1as ft 3 4.812x1as ft 3 Essentially no Region change (third
[USAR pg. 15.6-59) [USAR pg. 15.6-59) decimal point}
Volume of 6.84x1as ft 3 6.842x1as ft 3 Essentially no Containment change (third
[USAR pg. 15.6-59) [USAR pg. 15.6-59)
Unsprayed Region decimal point}
Volume of Total 9.6a7x1 as ft 3 9.6a7x1 os ft 3 No change Unsprayed Regions
[not currently specified [USAR pg. 15.6-59)
(including drywall}
separately in the USAR]
Attachment 1 L-14-245 Page 3of16 Flow Rate from 0-2 hours (hrs.) 3000 cubic 0 - 0.5 hour5.787037e-5 days <br />0.00139 hours <br />8.267196e-6 weeks <br />1.9025e-6 months <br /> (hr.) 0 cfm No actual change Drywall to feet per (Note: USAR Table 0.5-2 hrs. 3000 cfm Unsprayed Region minute 15.6-12b did not of the Containment (cfm) 2 - 720 hrs. 2.77x105 cfm reflect the zero flow
_ hrs. rate out of the 2 720 2 7,7x 105 cfm
_ [USAR Table 15.6-12b on
[USAR Table 15.6-12b on pg. 15*6-591 drywall during the first 0.5 hour5.787037e-5 days <br />0.00139 hours <br />8.267196e-6 weeks <br />1.9025e-6 months <br /> period pg. 15.6-59]
that was in the existing calculation)
Flow Rate from 0 - 2 hrs. 0 cfm 0 - 2 hrs. O cfm No actual change Unsprayed Region 2 - 720 hrs. 2. 77x105 cfm 2 - 720 hrs. 2.77x105 cfm (USAR markup of of the containment [USAR pg. 15.6-59] [USAR pg. 15.6-59] page 15.6-59 simply back to Drywell rounds 2. 765 to 2.77 x 105 cfm, which is the value in the existing calculation)
Primary 0.2 percent of containment 0.2 percent of containment No change Containment atmosphere per day (La) atmosphere per day (La)
Leakage Rate [USAR pg. 6.2-72 & 73; [USAR pg. 6.2-72 & 73; TS (sprayed and Technical Section 5.5.12]
unsprayed regions Specification (TS) leakage) Section 5.5.12]
Percent of Primary 89.92 percent 89.92 percent No change Containment (0.8992 La) (0.8992 La) (Rev. 0 of new Leakage that goes [USAR 15.6-31] [USAR 15.6-31] LOCA calculation Into the annulus used 100 percent, but Rev. 1 corrects that to 89.92 percent)
Percent of Primary 10.08 percent 10.08 percent No change Containment (0.1008 La) (0.1008 La)
Leakage that [USAR pg. 15.6-31] [USAR pg. 15.6-23 & 31) bypasses the Secondary Containment Credit for Not taken Based on containment Credit taken for Reduction in pressure reduction after reduction in Primary 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />, leakage is containment Containment reduced to 69 percent of pressure, as Leakage based on the value used during the permitted In containment first 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> RG 1.183. See pressure after pages 29 & 30 of
[USAR pg. 15.6-30]
24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> the RLA Degree of Conformance matrix
Attachment 1 L-14-245 Page 4of16 Credit for Not taken After 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />, leakage is Credit was taken for Reduction In reduced to 69 percent of reduction in Secondary the value used during the containment Containment first 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> pressure, as Bypass Leakage (USAR pg. 15.6-30) permitted in based on RG 1.183 containment pressure after 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> Containment Spray 1O minute auto initiation 30 minute manual initiation Initiation time is Initiation (based on high pressure [USAR 15.6-32) conservatively and LOCA signal) tripled, because.
[USAR 15.6-32] auto-initiation on containment high pressure might not be achieved Containment Spray 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> No change Duration [USAR pg. 6.5-12 & [USAR pg. 6.5-12 &
15.6-32] 15.6-32]
Spray Fall Height 53.2 feet 54.05 feet New calculation
[USAR pg. 15.6-59) [USAR pg. 15.6-59)
Containment Sprayed region of the Sprayed region of the Conservative Spray- Aerosol containment modelled containment modelled RADTRAD model (particulate) using STARNAUA using RADTRAD Powers assumption, Removal methodology model with 101h percentile RG 1.183, uncertainty distribution. Appendix A,
[USAR pg. 6.5-13, 14, 56, Particulate removal Section 3.3
& 58) coefficient due to sprays is (Note: In Am. 103, NRC reduced by a factor of 10 used RADTRAD after the aerosol mass is goth percentile uncertainty depleted by a factor of 50 distributions, per pg. 10 of the NRC SE for Am. 103) [USAR pg. 6.5-13, 14, &
56)
Other Inputs to Various (See USAR Q =0.0621 (Spray Flux) Powers spray model Spray Modeling Table 6.5-9 "Input inputs Alpha =1.422 (Ratio of Parameters For The Spray unsprayed volume to Removal Analysis" sprayed volume)
[USAR pg. 6.5-56]
[USAR pg. 6.5-56)
Attachment 1 L-14-245 Page 5of16 Containment Sprayed region of the Sprayed region of the RG 1.183 and Spray- Elemental containment modelled containment modelled SRP6.5.2 Iodine Removal using STARNAUA using Standard Review methodology Plan (SRP) 6.5.2 guidance. Elemental
[USAR pg. 6.5-13, 14, 56, Iodine removal by sprays
& 58) is terminated when a OF of up to 200 is reached
[USAR pg. 6.5-13, 14, &
56)
Natural Deposition- Drywall region modelled Drywall and unsprayed Conservative Aerosol using STARNAUA volume of containment RADTRAD "'odel (particulate) methodology modelled using RADTRAD assumption Removal Powers Model for aerosol
[USAR pg. 15.6-28 & 29) removal with 101h (Note: In Am. 103, NRC percentile uncertainty used RADTRAD 90lh distribution percentile uncertainty distributions, per pg. 7 of [USAR 15.6-28 & 29) the NRC SE for Am. 103)
Natural Deposition- Drywall region modelled Drywall, sprayed, and RG 1.183 and Elemental Iodine using STARNAUA unsprayed volume of SRP6.5.2 Removal methodology containment modelled (USAR pg. 15.6-30) using SRP 6.5.2 guidance.
Similar to the spray assumptions, elemental Iodine removal is terminated when a OF of up to 200 is reached
[USAR pg. 6.5-13, & Table 6.5-11)
Engineered Safety Time (hours) Leak Rate Time (hours) Leak Rate No change Feature (ESF) 0-24 15 gallons 0..24 15gph Leakage Pathway per hour 24-24.5 15 gph +
Direct to (gph) 50gpm Environment 24-24.5 15 gph + 24.5-720 15gph 50gpm
[USAR pg. 15.6-23, 33 &
24.5-720 15gph 60]
[USAR pg. 15.6-33 & 60]
Offsite Breathing Time (hours) Time (hours) RG 1.183, Rates (meters (m) 3/ 4 4 Section 4.1.3 0-8 3.47x10 0-8 3.5x10 second (sec))
8-24 1.75x104 8""'.'24 1.8x104 24-720 2.32x104 24-720 2.3x104
[USAR pg. 15.0-37) [USAR pg. 15.0-37)
Attachment 1 L-14-245 Page 6of16 Main Steam Line 250 standard cubic feet per 250 scfh total, 100 scfh No change (MSL) leak rate hour (scfh) total, 100 scfh maximum per line (under (standard maximum per line (under standard conditions).
conditions) standard conditions). Modelled as 100 scfh to
! Modelled as 100 scfh to the broken MSL, and the broken MSL, and 150 scfh to the intact 150 scfh to the intact MSL's MSL's
[TS SR 3.6.1.3.1 O]
[TS Surveillance Requirement (SR) 3.6.1.3.1 O]
Main Steam Line Flow rate from drywall to all Flow rate from drywall to No change leak rate converted steam lines (both broken the broken steam line (values in USAR from standard to and intact) = 298 cfh for = 1. 987 cfm for first 7484 Table 15.6-12a non-standard first 7484 seconds, and seconds, and 1.647 cfm appear to be conditions 247 cfh until 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> until 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> changed, but that is (assuming elevated Flow rate between MSIVs Flow rate from drywell to due to mathematical post-accident in one steam line = 191 cfh the intact steam lines conversion of .
temperatures) (Note: USAR Table = 2.98 cfm for first 7484 existing assumed during first 15.6-12a says cfm vs. cfh, seconds, and 2.47 cfm flow rates from cfh 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> which was a typographical until 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> to cfm (engineering error) Flow rate in one steam unit change only),
line, between the MSIVs and inclusion of
[USAR pg. 15.6-58]
= 3.183 cfm more detail into this Flow rate in the other (the table about how intact) steam lines, flow rates to (and between the MSIVs through) the main
=4.775 cfm steam lines are attributed to the
[USAR pg. 15.6-58]
broken versus the intact main steam lines)
Credit for Main Not taken After 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />, leakage Some credit was Steam line [USAR 15.6-25 & 58] from the drywell to the taken for reduction leakage reduction Main Steam Lines is in containment associated with reduced to 69 percent of pressure, as decreased the value used during the permitted in pressure after first 24 hrs. However, the RG 1.183 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />. leak rate assumed between the MSIVs is conservatively not reduced after 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> .
[USAR pg. 15.6-25 & 58]
Attachment 1 L-14-245 Page 7of16 Aerosol Removal Broken steam line - Broken steam line - No change Efficiencies in between MSIVs (100 scfh) between MSIVs (100 scfh)
Steam Lines - For Particulate Iodine, . - For Particulate Iodine, solubles, and insoluble solubles, and insoluble 68.1 % from 0 to 0.5 hr. 68.1 % from 0 to 0.5 hr.
83.5% from 0.5 to 1.5 hrs. 83.5% from 0.5 to 1.5 hrs.
87.13% from 1.5 to 3 hrs. 87.13% from 1.5 to 3 hrs.
89% from 3 to 5 hrs. 89% from 3 to 5 hrs.
86.14% from 5 to 7 hrs. 86.14% from 5 to 7 hrs.
81.85% from 7 to 9 hrs. 81.85% from 7 to 9 hrs.
76.9% from 9 to 11 hrs. 76.9% from 9 to 11 hrs.
36.53% from 11 to 720 hrs. 36.53% from 11 to 720 hrs.
-For Elemental Iodine - -For Elemental Iodine -
45% 45%
Intact Steam lines RPV to Intact Steam lines RPV to IB MSIV (150 scfh) 18 MSIV (150 scfh)
- For Particulate Iodine, - For Particulate Iodine, solubles and insoluble solubles and insoluble 72.06% from 0 - end 72.06% from 0 - end
- For Elemental Iodine - - For Elemental Iodine -
45% 45%
Intact Steam Lines Intact Steam Lines between MSIVs between MSIVs
- For Particulate Iodine, - For Particulate Iodine, solubles, and insoluble solubles, and insoluble 71.4% from Oto 0.5 hr. 71.4% from 0 to 0.5 hr.
81.3% from 0.5 to 1.5 hrs. 81.3% from 0.5 to 1.5 hrs.
83.61 % from 1.5 to 3 hrs. 83.61 % from 1.5 to 3 hrs.
84.49% from 3 to 5 hrs. 84.49% from 3 to 5 hrs.
83.39% from 5 to 7 hrs. 83.39% from 5 to 7 hrs.
79.98% from 7 to 9 hrs. 79.98% from 7 to 9 hrs.
75.58% from 9 to 11 hrs. 75.58% from 9 to 11 hrs.
38.07% from 11 to 720 hrs. 38.07% from 11 to 720 hrs.
-For Elemental Iodine - -For Elemental Iodine -
45% 45%
[USAR pg. 15.6-26 & 27 [USAR pg. 15.6-26 & 27 provide general discussion provide general of steam line treatment] discussion]
Annulus Exhaust Not considered, such that Not considered, such that No change Gas Treatment flow rate to the flow rate to the (AEGT) system =
environment 2000 cfm =
environment 2000 cfm recirculation to the
[Not currently specified in [USAR pg. 15.6-31]
annulus the USAR]
AEGT Filtration 99 percent efficiency 99 percent efficiency No change (High Efficiency [USAR pg. 15.6-31 & 59] [USAR pg. 6.5-4; 15.6-31 Particulate Air & 59)
(HEPA) filter)
Attachment 1 L-14-245 Page 8of16 AEGT Filtration Zero percent efficiency Zero percent efficiency No change (Charcoal)
[USAR pg. 6.5-3) [USAR pg. 6.5-3 & 42)
Exclusion Area 4.3x10-4 4.3x10-4 No change Boundary (EAB)
[NRC Safety Evaluation for [USAR pg. 15.6-63)
X/Q (sec/m 3 )
Amendment 103, pg. 15)
Low Population Time (hrs) Time (hrs) No change Zone (LPZ) 0-8 4.8x1Q*S 0-8 4.8x10-5 X/Q (sec/m 3 )
8-24 3.3x1Q*S 8-24 3.3x10-5 24-96 1.4x1Q*S 24-96 1.4x10-5 96-720 4.1x10.a 96-720 4.1x10.a
[NRC Safety Evaluation for [USAR pg. 15.6-63)
Amendment 103, pg. 15)
Control Room X/Q Time (hrs) Time (hrs) No change (sec/m 3 ) (markups on USAR 0-8 3.5x10-4 0-8 3.5x10-4 page 15.6-63 are 8-24 2.1x10-4 8-24 2.1x10-4 correcting incorrect 24-96 1.1x10-4 24-96 1.1x10-4 information)96-720 5.75x10-5 96-720 5.75x10-5
[NRC Safety Evaluation for [USAR pg. 15.6-63 with Amendment 103, pg. 14) corrections to reflect correct CLB]
Control Room 3.44x105 ft 3 3.90x105 ft 3 Calculation for Volume control room volume
[USAR pg. 15.6-64) [USAR pg. 15.6-64) revised since pilot plant submittal Control Room 95 percent credit for HEPA 99 percent credit for HEPA Acceptable value Filtration System removal of Particulates. removal of Particulates based on current (HEPA) and future TS test
[USAR pg. 15.6-35) [USAR pg. 6.5-4; 15.6-35) acceptance criterion Control Room 50 percent charcoal filter 80 percent charcoal filter Eliminated an Filtration System efficiency for elemental and efficiency for elemental unnecessary (Charcoal) organic iodine. and organic iodine. conservatism; 80 percent value will
[USAR pg. 6.5-4, 15.6-23 & [USAR pg. 6.5-4 & 30, support a future
- 35) 15.6-23 & 35) request for licensing action to revise TS charcoal adsorber testing acceptance criterion to a value of 10% penetration
(=90% efficiency) versus the current 2.5% penetration requirement
Attachment 1 L-14-245-Page 9of16 Control Room 30 minutes 30 minute manual operator No credit taken for Emergency actuation automatic actuation
[USAR pg. 6.4-8, 15.6-23)
Recirculation of filtration or for
[USAR pg. 6.4-8, 14, & 15, System any reduction in 15.6-23 & 35 ActuationfTiming of unfiltered In-leakage the Start of until 30 minutes, to Filtration support a future request for licensing action to remove TS controls over auto-initiation instrumentation Timing of the 1375 cfm unfiltered 6600 cfm unfiltered Conservatively Reduction of inleakage starting at inleakage from t=O to assumes outside air Unfiltered time (t)=O, for duration 30 minutes inlet is not isolated lnleakage Into the until t=30 minutes
[USAR pg. 6.4-14 & 15, 1375 cfm from t=30 min to Control .Room when Control Room 15.6-35 & 64) 30 days Emergency
[USAR page 6.4-14 & 15, Recirculation 15.6-35 & 64) System is manually actuated, to support a future request for licensing action to remove TS controls over auto-initiation instrumentation Control Room 3.47x10-4 m3/sec 3.5x10-4 m 3/sec RG 1.183, Breathing Rate Section 4.2.6
[USAR pg. 15.0-37) [USAR pg. 15.0-37)
Control Room Time (hours) Time (hours) No change Occupancy Factors 0-24 1.0 0-24 1.0 24-96 0.6 24-96 0.6 96-720 0.4 96-720 0.4
[not currently specified in [USAR pg. 15.6-64) the USAR]
CRDA (Scenario 1 -Standard Review Plan Section 15.4.9)
Current Licensing Basis Proposed Licensing Basis Parameter Basis For
, [Current Location] [Proposed Location] Changes Core Source Term GE14 GNF2 Change in basis fuel design
[USAR pg. 15.4-27, 45, & [USAR pg. 15.4-27, 45, & 46) 46]
Attachment 1 L-14-245 Page 10of16 Power Level Plant startup, at low power Plant startup, at low power level, No change level, after operation at after operation at 3,833 MW1 3,833MW1
[USAR pg. 15.4-26 thru 29, & 44)
[USAR pg. 15.4-26 thru 29,
&44)
Coincident loss of Yes Yes No change offsite power (per
[USAR pg. 15.4-27 & 28] [USAR pg. 15.4-27 & 28]
(LOOP)? SRP 15.4.9 Section Ill, Assumption 1)
Isotopes Considered Iodine, Considered Iodine, Krypton, Added Considered Krypton, and Xenon Xenon, Bromine, Cesium, and Isotopes per isotopes Rubidium isotopes RG 1.183, Section 3,
[USAR pg. 15.4-29] [USAR pg. 15.4-29]
Tables 3 & 5 Assumed number 1107 1376 (two* full rows of bundles Conservative of failed fuel rods around the dropped control rod) increase In
[USAR pg. 15.4-27, 28, &
number of 44] [USAR pg. 15.4-27, 28, & 44]
failed rods Iodine Fractions, % Organic 0 Organic 0.15 RG 1.183, Elemental 100 Elemental 4.85 Appendix C, Particulate 0 Particulate 95.0 Item 3.6
[USAR pg. 15.4-44] [USAR pg. 15.4-44]
Radial Peaking 1.7 2.0 Current radial Factor peaking
[Reload Analysis [Reload Analysis Parameter]
factor in Parameter]
analyses Gap and Melt Group Gap Melt Group Gap Melt Added alkali fraction Noble Gas 10% 100% Noble Gas 10% 100% metals per Halogen 10% 50% Halogen 10% 50% RG 1.183, Alkali Metals 12% 25% Section 3.2,
[USAR pg. 15.4-29] Tables 1 & 3
[USAR pg. 15.4-29]
Activity released to Group Group RG 1.183, condenser Noble Gas 100% Noble Gas 100% Appendix C, Halogen 10% Halogen 10% Item 3.3 Remaining 1%
[USAR pg. 15.4-29]
[USAR pg. 15.4-29]
Activity available Group Group RG 1.183, for release from Noble Gas 100% Noble Gas 100% Appendix C, condenser Halogen 10% Halogen 10% Item 3.4 Particulate 1%
[USAR pg. 15.4-29]
[USAR pg. 15.4-29]
Attachment 1 L-14-245 Page 11of16 Condenser The leakage rate from the The leakage rate from the No change Leakage condenser is assumed to condenser is assumed to be be 1% per day for the 1% per day for the duration of the duration of the event event (24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />)
(24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />).
[USAR pg. 15.4-29]
[USAR pg. 15.4-29 (24 hour2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> termination time is from SRP 15.4.9 Assumption 111.12)]
Release to All activity leaking from the All activity leaking from the No change Environment condenser is assumed to condenser is assumed to leak leak directly to the directly to the environment environment without mixing without mixing in the turbine in the turbine building. building.
[USAR pg. 15.4-28 & 44] [USAR pg. 15.4-28 & 44]
Atmospheric Time EAB LPZ Time EAB LPZ CR No change Dispersion X/Q except for the 0-2 hrs. 4.3E-4 4.SE-5 0-2 hrs. 4.3E-4 4.8E-5 3.5E-4 addition of 2-8 hrs. -- 4.SE-5 2-8 hrs. -- 4.8E-5 3.5E-4 control room 8-24 hrs. -- 3.3E-5 8-24 hrs. -- 3.3E-5 2.1 E-4 (CR) X/Q's 1-4 Days -- 1.4E-5 1-4 Days -- 1.4E-5 1.1 E-4 4-30 Days -- 4.1 E-6 4-30 Days -- 4.1 E-6 5. 75E-5
[USAR pg. 15.4-45] [USAR pg. 15.4-45]
Control Room Dose Not calculated Calculated RG 1.183, Section 4.4
[Control room doses were [USAR pg. 15.4-47]
not previously required to be determined for CRDA]
Control Room NIA Not credited No credit Emergency taken
[Control room doses were [USAR pg. 6.5-4 & 30, 15.4-45]
Recirculation not previously required to System Filtration be determined for CRDA]
(Charcoal and HEPA)
AEGT System Not cr~dited Not credited No change Filtration (Charcoal
[Releases are from outside [USAR pg. 6.5-3, 4, & 42]
and HEPA) containment, so AEGT system is N/A, therefore it is not credited]
Attachment 1 L-14-245 Page 12of16 CRDA (Scenario 2 - NED0-31400 11 Safety Evaluation for Eliminating the Bolllng Water Reactor Main Steam Line Isolation Valve Closure Function and Scram Function of the Main Steam Line Radiation Monitor")
Parameter Current Licensing Basis Proposed Licensing Basis Basis For
{See Scenario 1,
[Current Location] [Proposed Location] Changes with the following changes based on NED0-31400}
Power Level Plant startup, at low power Plant startup, at low power level, No change level, after operation at after operation at 3,833 MW1, 3,833 MW1, aligned to the aligned to the Offgas system Offgas system
[USAR pg. 15.4-26, 27, 28, & 30)
[USAR pg. 15.4-26, 27, 28,
& 30)
Coincident loss of No, so Offgas System No, so Offgas System remains No change offsite power remains running to hold up running to hold up all but the (LOOP)? all but the noble gases noble gases
[USAR 15.4-30) [USAR 15.4-30)
MSLBOC Current Licensing Basis Proposed Licensing Basis Basis for Parameter [Current Location] [Proposed Location] Changes Reactor Coolant Original GE-supplied Revised GE-supplied reactor RG 1.183, Inventory reactor coolant inventory coolant inventory for: Appendix D, for: =
a) Design basis analysis TS pre- Assumption 2 a) Design basis analysis = accident spike of 4.0 µCi/gm, and TS pre-accident spike of b) Realistic analysis =
4.0 microcuries (µCi)/ TS maximum equilibrium value of gram (gm), and 0.2 µCi/gm b) Realistic analysis = [USAR pg. 15.6-13 & 15)
TS maximum equilibrium value of 0.2 µCi/gm
[USAR pg. 15.6-13 & 15]
Source Term Considered Iodine, Krypton, Considered Iodine, Krypton, Revised and Xenon isotopes as Xenon, and Bromine isotopes as GE-supplied coolant activity coolant activity reactor
[USAR pg. 15.6-52 & 56) [USAR pg. 15.6-52 & 56) coolant isotopes Iodine Fractions Organic 0 Organic 0.15 RG 1.183,
(%) Elemental 100 Elemental 4.85 Appendix D, Particulate 0 Particulate 95.0 Assumption
[USAR pg. 15.6-54] [USAR pg. 15.6-54) 4.4
Attachment 1 L-14-245 Page 13of16 Isolation Valve Various closure times are The supporting calculation's. Clarification Closure Time, listed on current USAR conservative valve closure time of of actual and mass of pages, but the resultant 6.05 seconds will be reflected in (conservative) coolant released mass release (consisting of the USAR, with its resultant mass valve closure to the 14,311 pounds.of steam release of 14,311 pounds of timing in the environment and 127 ,376 pounds of steam and 127,376 pounds of existing liquid) listed in the USAR is liquid calculation; consistent with the no change in
[USAR 15.6-12 & 13]
supporting calculation the amount of reactor
[USAR 15.6-12 & 13]
coolant released Atmospheric EAB LPZ Time EAB LPZ CR Utilized Dispersion X/Q updated X/Q
- 6. 7E-4 8.2E-5 0-2 hrs. 4.3E-4 4.8E-5 3.5E-4 values and 2-8 hrs. -- 4.8E-5 3.5E-4
[USAR pg. 15.6-55] added control 8-24 hrs. - 3.3E-5 2.1 E-4 room 1-4 Days - 1.4E-5 1.1E-4 4-30 Days - 4.1 E-6 5. 75E-5
[USAR pg. 2.3-89 & 15.6-55]
Control Room Not calculated Calculated RG 1.183, Dose Section 4.4
[Control room doses were [USAR pg. 15.6-53, 55 & 57) not previously required to be determined for MSLBOC]
Control Room N/A Not credited No credit Emergency [Control room doses were taken
[USAR pg. 6.5-4 & 30)
Recirculation not previously required to System Filtration be determined for (Charcoal & MSLBOC]
HEPA)
AEGT System Not credited Not credited No change Filtration
[Releases are from outside [USAR pg. 6.5-3, 4, & 42)
(Charcoal and containment, so AEGT HEPA) system is NIA, therefore it is not credited]
L-14-245 Page 14of16
- 2. On page 7 of the submittal evaluation, FirstEnergy Nuclear Operating Company addressed the impact of the proposed* changes on the radiological habitability of the Technical Support Center. However, the application appears to be silent on the impact of those changes on the calculations supporting the establishment of numeric thresholds for emergency action levels (EALs) related to readings on: (1) radiological effluent radiation monitors, and (2) the in-containment high range radiation monitor readings used in the fission product barrier matrix EALs. In addition to the source term change and core inventory changes, the NRC staff notes that you have proposed changes in other analysis assumptions (e.g., filter removal efficiencies, containment leakage rates, drywell flows, containment spray credit, etc.) that could potentially affect the validity of the previous EAL thresholds. Explain the impact of the changes on these EAL thresholds.
Response: The current PNPP Emergency Plan utilizes the Nuclear Utility Management and Resources Council (NUMARC) EAL methodology, NUMARC/NESP-007, Methodology for Development of Emergency Action Levels. When the plant was originally licensed in the mid-1980's, the dose assessment program utilized a source term based on the licensing-basis loss of coolant accident (LOCA) in the Final Safety Analysis Report (FSAR). Subsequently, in October of 1988, the NRC published NUREG-1228, Source Term Estimation During Incident Response to Severe Nuclear Power Plant Accidents. This guidance reflected a more current understanding of accident source terms and their offsite consequences. The NUREG noted on page 1-6 that licensing basis evaluations ."normally should not be used to estimate actual accident source terms or offsite doses." The NUREG (beginning on page 2-5) provided core inventory
- assumptions to be used for source term estimation, expressed in curies per electrical megawatt (Ci/MWe), such that the source term could be adjusted for various plants. The NUREG explained on page 1-2 that "studies of the uncertainties associated with source term estimation indicate that source term projections based on accident conditions are only accurate within a factor of 100 or more ... " Therefore, the generic, scalable source term provided by NUREG-1228 is considered to provide an acceptable standard for use at various plants, including PNPP. In the early 1990s at PNPP, when dose assessment software was updated, the source term provided in NUREG-1228, scaled for PNPP's licensed power level at that time, was utilized.
- The dose assessment program was updated again in 2012, utilizing the Meteorological Information and Dose Assessment Software (MIDAS) program. As noted in NUREG-1228 on page 1-3, "if a change in assumptions does not result in a change to the source term by at least 1 order of magnitude, it is not worth considering ... " Therefore, it was determined that the NUREG-1228 source term, scaled for PNPP's five percent uprate, would be used as input for the dose assessment program (for events postulated to occur with the plant at power). The.dose assessment program was utilized to back-calculate plant effluent monitor values that would result in 1 Rem Total Effective Dose Equivalent (TEDE) and/or 5 Rem Child Thyroid doses offsite (the current EAL thresholds).
Similarly, for item (2) in the NRC RAI (the in-containment high-range radiation monitors),
the PNPP EALs are based on the NUMARC/NESP-007 guidance. That guidance L-14-245 Page 15of16 discusses the determination of in-containment radiation monitor readings for fuel failure events, specifically, for the fuel clad barrier on page 5-20 and the primary containment barrier on page 5-23. Pag~ 5-23 includes a reference to NUREG-1228. Similar to the discussions above for the effluent radiation monitors, the NUREG-1228 conclusion that unless a change in assumptions results "in a change to the source term by at least .1 order of magnitude, it is not worth considering" can also be applied to the In-containment radiation monitor reading thresholds. Since the licensing basis source term is not changing significantly with the adoption of the GNF2 fuel, and a NUREG-1228-based source term based on curies per electrical megawatt would not change, it is concluded that the PNPP in-containment radiation monitor reading values specified in the EALs do not need to be changed as a result of the proposed change to the licensing basis source term for the LOCA event.
In summary, it is concluded that implementation of a new licensing basis source term, such as proposed by this request for licensing action (RLA), does not invalidate the current numeric thresholds in the Emergency Plan EALs, including the (1) radiological effluent radiation monitors, and (2) the in-containment high range radiation monitors.
Other proposed changes to licensing basis analysis assumptions, such as those listed in the NRC RAI (filter efficiencies, containment leakage rates, drywell flows, containment spray credit, etc.), also would not invalidate use of the current numeric thresholds in the EALs.
- 3. Address whether any non-safety-related systems and components are credited in the accident source term (AST) analyses. If so:
- a. Describe the independence (electrical and physical separation) of these systems from the safety-related systems. Provide a detailed discussion on why a fault on the non-Class 1E electrical circuit will not propagate to the Class 1E electrical circuit.
- b. Describe the redundancy of these systems and how these systems meet the single failure criterion.
Response: No non-safety-related systems or components are credited to reduce doses in the alternative AST analyses. Conservative assumptions in several event dose analyses assume the normal control room ventilation system continues to operate for various lengths of time post-accident, which increases the amount of unfiltered inleakage into the control room versus use of an assumption that the systems shut down or otherwise isolate quickly, so this is not considered to be a 'credit.' The Scenario 1 CRDA analysis notes that if the mechanical vacuum pumps are running at a very low plant power level, the pumps will shut down as a result of the Standard Review Plan 15.4.9-required Assumption 1 of a loss of offsite power (LOOP); this has been previously reviewed and approved by the NRC for the CRDA at PNPP.
Attachment 1 L-14-245 Page 16of16
- 4. Address whether any loads are being added to the emergency diesel generators (EDGs). If so, describe their Impact on the capability and capacity of the EDGs. Also, describe changes, if any, being made to the EOG loading sequence to support this license amendment request.
Response: No new loads are being added to the EDGs, and there are no changes being made to the EDG loading sequence in support of this amendment request.
- 5. Discuss why there are no changes to the Environmental Qualification profiles as a result of the full implementation of the AST.
Response: A calculation was performed to determine the impact on equipment environmental qualification due to the post-accident fuel failure radiation dose for GNF2 fuel. The maximum radiation dose rate and the integrated dose (over the course of an
. accident) following failure of GNF2 fuel was compared to the maximum dose rate and the integrated dose for the current design basis source term. It was determined that the post-accident doses from the GNF2 source term trended closely with the original source term, with the GNF2 fuel post-accident doses being slightly higher. The increases for the maximum dose rates were on the order of 10.5 percent, and the integrated dose increases ranged from zero percent to approximately eight percent. The increases represent the expected change in the post-accident dose profiles as a result of the transition to the GNF2 fuel. Equipment Qualification packages were reviewed to determine if these increases would exceed the existing radiation qualification of equipment. In all cases, the existing qualification doses bound the expected increased doses resulting from the transition to GNF2 fuel. Formal updates to the environmental
- qualification zone profiles, equipment calculations, and affected auditable file packages, are ongoing to reflect the results of the above review of the GNF2 post-accident doses.
Attachment 2 L-14-245 Effects of Necessary Changes to Supporting Radiological Dose Calculations Page 1of76 Several necessary changes were identified in two of the calculation summaries included as addendums to the request for licensing action (RLA) submitted on December 6, 2013; specifically Addendum 4, "Summary of Loss of Coolant Accident (LOCA) Dose Calculation," and Addendum 5, "Summary of Control Rod Drop Accident (CRDA) Dose Calculation." Updated summaries of the calculations are included in this attachment, following this discussion (42 pages in the LOCA summary, and 2 pages in the CRDA summary). The issue of these calculations needing to be changed after their submittal has been entered into the FENOC Corrective Action Program.
As a result of the calculation changes, and a re-examination of the proposed Updated Safety Analysis Report (USAR) markups that were included as Addendum 1 of the RLA, updates of the proposed USAR markups are also provided at the end of this attachment, immediately following the CRDA dose calculation update (31 revised or additional USAR pages (the new pages do not include revised USAR text - they are provided only for the purpose of providing information/context)).
The changes to the LOCA calculation include:
- 1) Correction of the total elemental iodine removal coefficient in the sprayed region of containment to 20.975 hour1,
- 2) Correction of the equilibrium source term values for Y90, Y91, Y92, Zr95, Zr97, Nb95, and Mo99,
- 3) Correction of engineered safety feature (ESF) leakage timing so that ESF leakage is assumed throughout the 720 hours0.00833 days <br />0.2 hours <br />0.00119 weeks <br />2.7396e-4 months <br /> of the analysis,
- 4) Removal of the unnecessary hydrogen mixing system model (sensitivity),
- 5) Increase of the unfiltered flow rate into the control room during the first 30 minutes to be consistent with the value assumed in the CRDA and main steam line break analyses (10 percent above nominal system intake flow rate),
- 6) Corrected containment leakage flow rates into the annulus (secondary containment),
and
- 7) Additional changes to improve readability and flow of information.
The change to the CRDA calculation clarifies the description of the iodine releases assumed in the calculation.
TABLE OF CONTENTS Page i SUBJECT COVERSHEET:
Table of Contents OBJECTIVE OR PURPOSE SCOPE OF CALCULATION
SUMMARY
OF RESULTS/CONCLUSIONS LIMITATIONS OR RESTRICTIONS ON CALCULATION APPLICABILITY IMPACT ON OUTPUT DOCUMENTS DOCUMENT INDEX CALCULATION COMPUTATION (BODY OF CALCULATION):
1.0 PURPOSE .............-....................................................................................................*.................................................. 1
2.0 BACKGROUND
...***..*...**.*.*.....*..............*.*..*.*....***.....**..*...*............................*........*.*..**..*..**.**.*..*.**..*...**.....**...*.....***1 3.0 ACCEPTANCE CRITERIA ***.*...****.*....******.**.****..**.**********..**...*********.***..*****....*.***..******.***********.*********************.******.********** z 4.0 METHOD OF ANALYSIS *.....*.............*.......*.*...**..*.*...**...**.*........*.*.....*...*..*...*....*..*.********.***********.*****..*......*..*....*****...**3 5.0 ASSUMPTIONS ...*****.....**.....***............**........*....***....***.......**.....**........*.......*..*...****...****...*.******...***......**...............*...*3 5.1 CONTROL ROOM EMERGENCY RECIRCULATION SYSTEM (CRERS) ***************************************************************************************************** 3 5.2 HYDROGEN MIXING SYSTEM.*************************************************.*************************************************************************************************** 3 5.3 CONTROL ROOM INLEAKAGE ...................................................................................................................................................... 4 5.4 DRYWELLFLOWS ..................................................................................................................................................................... 4 5.5 CONTAINMENT LEAKAGE RATE ................................................................................................................................................... 5 5.6 AEGTS FILTRATION ................................................................................................................................................................. 5 5.7 CONTAINMENT SPRAY ...................................................................................................................................~ .......................... 5 5.8 ECCS LEAKAGE ....................................................................................................................................................................... 6 5.9 MSIV LEAKAGE RATE *************************************************************************************************************************************************************** 6 5.10 BYPASS LEAKAGE ..................................................................................................................................................................... 7 5.11 SOURCE TERM RELEASE ************************************************************************************************************************************************************ 1 6.0 DESIGN INPUT .......................................................................................*................................................................~****8 6.1 PLANT GRADE ..................................................................:...............................................................~ ...................................... 8 6.2 CORE SOURCE TERMS AND RELEASES ........................................................................................................................................... 8 6.2.J Onset of Gap Release ............................................................................................................................................. JO 6.2.2 Release fractions .................................................................................................................................................... JO 6.3 SUPPRESSION POOL IODINE RE-EVOLUTION .................................................................................................................................. 10 6.4 DOSE CONVERSION FACTORS .......................................................................................................~ ********************************************* 10 6.5 ATMOSPHERIC DISPERSION FACTORS **********************************************, ******************************************************************************************** 11 6.6 BREATHING RATE AND OCCUPANCY FACTORS ****************************************************************************************************************************** :. 11 6.7 CONTAINMENTVOlUMES .......................................................................................................................................................... 12 6.8 TECHNICAL SUPPORT CENTER DOSES ******************************************************************************************************************************************* 12 6.9 MIXING BElWEEN THE UNSPRAYED CONTAINMENT AND SPRAYED CONTAINMENT ............................................................................... 13 6.10 CONTAINMENT LEAKRATE .......................................................................................................................................................... 13 6.11 LEAKAGE AFTER 24*HouRS ........................................................................................................................................................ 14 6.12 MSIV FLOWS ************************************************************************************************************************************************************************* 15 6.13 RADIONUCLIDE REMOVAL MECHANISMS ************************************************************************************************************************************** 16
Page ii 6.13.1 Removal by Deposition ...................................................................................................................................... 16 6.13.2 Removal by Sprays ............................................................................................................................................. 19 6.14 ANNULUS MODEL .................................................................................................................................................................... 24 6.15 DEPOSITION IN MAIN STEAM LINES ............................................................................................................................................. 24 7.0 ACCIDENT SCENARIO AND CHRONOLOGY ...........................................................................-**--*********oooooo******H******25 8.0* MODEL DEVELOPMENT ********************************************************************************************************-*---**************************26 8.1 ECCS LIQUID LEAKAGE ............................................................................................................................................................. 26 8.1.1 *Source Terms ........................................................................................................................~................................. 26 8.1.2 Volumes.................................................................................................................................................................. 27 8.1.3 Flows ...................................................................................................................................................................... 27 8.1.4 Removal Mechanisms ............................................................................................................................................ 27 8.1.S Model .......................................................................... :.......................................................................................... 27 8.1.6 Results .................... ;............................................................................................................................................... 27 8.2 MSIV LEAKAGE ....................................................................................................................................................................... 27 8.2.1 Source Terms ........................................................................................:................................................................. 27 8.2.2 Volumes.................................................................................................................................................................. 28 8.2.3 Flows_ ...................................................................................................................................................................... 28 8.2.4 Release Points ........................................................................................................................................................ 28 8.2.5 Model ..................................................................................................................................................................... 29 8.3 CONTAINMENT & CONTAINMENT BYPASS LEAKAGE ........................................................................................................................ 29 8.3.1 Volumes.................................................................................................................................................................. 29 8.3.2 Flows ...................................................................................................................................................................... 30 8.3.3 Removal Mechanisms ............................................................................................................................................ 31 8.3.4 Release Points ........................................................................................................................................................ 32 8.3.S Model ...:................................................................................................................................................................. 32 8.4 CONTROL ROOM ..................................................................................................................................................................... 32 8.5 RADTRAD MODEL ................................................................................................................................................................ 33 9.0 OPERATOR ACTIONS ****************************************************************************************************************-******************************33 10.0 CO~PUTATION *************************************************************************************************************************-*****************************36 11.0 OVERALL RESULTS .................................................................................................................... --*****************************36 ATTACHMENTS : PNPP ESF.out 25 Pages : PNPP LOCA.out 338 Pages : PNPP LOCA TSC.out 42 Pages : PNPP ESF TSC.out 26 Pages SUPPORTING DOCUMENTS (For Records Coav Onlv\
Page iii OBJECTIVE OR PURPOSE:
This calculation replaces the current loss-of-coolant accident (LOCA) dose calculation (PSAT 08401T.03, DIN 25). and supports the transition to GNF2 fuel. In addition, certain excess conservatisms contained in the current LOCA dose calculation will be removed to increase the margin of safety. This calculation will be performed in accordance with the guidance provided in Regulatory Guide 1.183 (DIN 7) for application of an alternative radiological source term and will demonstrate that the offsite and onsite post-accident doses comply with the requirements and acceptance criteria *of 10 CFR Part 50.67.
SCOPE OF CALCULATION/REVISION Revision*o PNPP will be transitioning to GNF2 fuel in future outages. The purpose of this calculation is to prepare a dose analysis supporting this transition and to establish the new design basis LOCA dose analysis using the RADTRAD 3.03 computer program, which was developed for the Nuclear Regulatory Commission (NRC) and is in common use for this type of application in the nuclear industry. This calculation may also be used to support a license amendment request (LAR) associated with the GNF2 fuel transition.
Revision 1 The changes incorporated In Revision 1 are: 1) Correction of the total elemental iodine removal coefficient for the sprayed region to 20.975 hr1, 2) Correction of the equilibrium core source term for Y90, Y91, Y92, Zr95, Zr97, Nb95, and Mo99, 3) Correction of the ESF leakage timing, and 4) removal of the unnecessary hydrogen mixing system model (sensitivity). Revision 1 also incorporates Addendum A-01 and Post-It-Note P-01.
SUMMARY
OF RESULTS/CONCLUSIONS The post-accident offsite, Control Room, and Technical Support Center doses for a postulated design basis LOCA meet the requirements of 10 CFR Part 50.67. The LOCA dose results, including all leakage pathways, from Table 11-1, are given below:
Location LOCA Dose remTEDE 21.2 6.9 3.0 0.5 LIMITATIONS OR RESTRICTIONS ON CALCULATION APPLICABILITY:
This calculation determines the radiological dose consequences resulting from the reader coolant release that accompanies a postulated design basis LOCA, which are reported in USAA Section 15.6.5.
This calculation will become the licensing basis LOCA dose analysis after the transition to GNF2 fuel.
IMPACT ON OUTPUT DOCUMENTS The results of this calculation will be incorporated into the USAR following LAR approval.
Page iv DOCUMENT INDEX 8
c z
0 c
i5 Document Numbermtle Revision, Edition, Date I!
J!
/!}_
-:J D.
c s
~
1 Safety Evaluation by the Office of Nuclear Reactor Regulation Related to N/A 181 0 D Amendment No. 103 to Facility.Operating License No. NPF-58 2 NUREG/CR-6604, RADTRAD: A Simplified Model for Radionuclide Transport December 181 0 D and Removal and Dose Estimation 1997 3 NUREG-1465, Accident Source Terms for Light-Water Nuclear Power Plants February 181 0 D 1995 4 Federal Guidance Report 11, Limiting Values of Radionuclide Intake and Air Second 181 D D Concentration and Dose Conversion Factors for Inhalation, Submersion, and Printing, 1989 Ingestion 5 Federal Guidance Report 12, External Exposure to Radionuclides in Air, Water, September 181 0 D and Soil 1993 6 NUREG/CR-5966, A Simplified Model of Aerosol Removal by Containment June 1993 181 0 D Sprays 7 Regulatory Guide 1.183, "Alternative Radiological Source Terms for Evaluating July2000 181 D 0 Design Basis Accidents at Nuclear Power Reactors*
8 Not Used 0 0 D 9 GEH-KL1WX23P-017, from E. G. Thacker II (GE) to E. S. Tomlinson Ill May7, 2012 D 181 D (FENOC), PNP GNF2 Fuel Transition: F0802 Source Term Output Files 10 DES/98-0845, Telephone and Conference Memorandum by Paul J. 1212198 0 181 D Roney/DES, Perry Control Room Atmospheric Dispersion Factors (Chl/Q) 11 PSAT 150.01C.03, Dose Calculation Data Base for Application of the Revised Revlslon2 0 181 0 OBA Source Term to the Perry Power Uprate 12 PSAT 04202H.04, Aerosol Decay Rates (Lambda) in Drywall RevisionO 0 181 0 13 PSAT 04202U.03, Dose Calculation Data Base for Application of the Revised Revision2 D 181 0 OBA Source Term to the CEI Perry Nuclear Power Plant 14 10 Code of Federal Regulations 50.67, Accident Source Terms December 23, 181 0 D 1999 15 PNPP Technical Specifications Amendment 0 181 0 150 16 M26-001, M26, Volume Calculation, Control Room Envelope Revision2 0 181 0 17 PSAT 04202H.13, Offsite and Control Room Dose Calculation Revision 1 ti 181 0 18 PERRYUSAR Revision 17 181 0 D
Pagev 8c 0 !? 'S z Revision, 'S c
i=i Document Number/T"itle Edition, Date ! a.
..s ~
19 NEI 99-03, Control Room Habitability Assessment Guidance March2003 181 D D 20 Regulatory Guide 1.52, "Design, Inspection, and Testing Criteria for Air Revision2, 181 D D Filtration and Adsorption Units of Post-Accident Engineered-Safety-Feature March 1978 Abnosphere Cleanup System~ In Light-Water-Cooled Nuclear Power Plants" 21 PNPP Technical Specification Section 5.5.7, PNPP Ventilation Filter Testing Amendment 181 D D Program (VFTP) 143 22 NUREG/CR-6604, Supplement 1, RADTRAD: A Simplified Model for June8, 1999 181 D D Radionuclide Transport and Removal and Dose Estimation 23 NUREG/CR-6604, Supplement 2, RADTRAD: A Simplified Model for October2002 181 D D Radionuclide Transport and Removal and Dose Estimation 24 10 Code of Federal Regulations 20, Standards For Protection Against Oct. 1, 2007 181 D D Radiation 25 PSAT 08401T.03, Peny Plant Total Effective Dose Equivalent (TEDE) Revision 5 D 181 D Calculation 26 PNPP Calculation 3.2.15.17, Containment Water Pool pH Post-Accident RevisionO D 181 D 27 GE letter from D. Braden (GE) to E. Root (CEI), GE-PAIP-651, ORF A22- NIA D 181 D 00084-00, dated 3/12101, *Additional Containment Response Cuives" 28 10 Code of Federal Regulations Part 50 - Domestic Licensing of Production and 17 FR 39906, 181 D D Utilization Facilities Jul. 6, 2012 29 10 Code of Federal Regulations Part 100- Reactor Site Criteria 77 FR39910, 181 D D Jul. 6, 2012 30 RADTRAD Computer Program Certification, FNOCPP184, CEl-120 181 D D 31 CEI Calculation 3.2.6.4, Post-LOCA Doses with Spray at 10 min for 6 Hours RevisionO 181 D D and Control Room lnleakage of 90 CFM 32 Wolfram Mathworfd httj!://mgthworfd.wglfram,com/Oblalg§Rheroid.!Jlml accessed 181 D D 712012012 33 NUREG/CR-0009, Technological Bases for Models of Spray Washout of 0 181 D D Airborne Contaminants in Containment Vessels 34 NUREG-800, Standard Review Plan (SRP) 6.5.2, Containment Spray As A Revlsion4, 181 D 0 Fission Product Cleanup System March2007 35 PNPP Drawing 320-0661-00000, Containment Spray System RevlsionT D 181 D 36 PNPP Drawing D-314-861, Sheet 3, Containment Vessel Spray Ring "A" Piping RevisionB D 181 D 37 PNPP Drawing D-314-661, Sheet 8, Containment Vessel Spray Ring *e* - RevlsionB D 181 D
Page vi 8c z
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Revision, 2!
~
- I i5 Document Numberfrdle Edition, Date ~ 6 Piping 38 PNPP drawing Ss-304-661, Sheet 105.2, Piping Isometric-Containment Spray RevisionC 0 181 0 System 39 PNPP Drawing D-314-661, Sheet 7, Containment Vessel Spray Ring "D" RevisionB 0 181 0 40 PNPP Drawing SS-304-661, Sheet 102.2, Piping Isometric-Containment RevlsionB 0 *181 D Spray System Reactor Building 41 PNPP Drawing D-314-661, Sheet 6, Containment Vessel Spray Ring "F" Revision B D 181 0 42 PSAT 04202H.08, Steamline: Particulate Decontamination Calculation. Revision 1 D 181 0 43 PSAT 04212H.02, Drywell Sweep-Out Rate and Related Thermal-Hydraulic Revision 1 181 D 0 Conditions Inside Containment 44 NUREG-0800, Standard Review Plan, 15.6.5, Appendix B, Radiological Revision 1, 181 D 0 Consequences of a Design Basis L~f-COOlant Accident: Leakage from July 1981 Engineered Safety Feature Components Outside Containment 45 PNPP Drawing 511-0016-00000, Reactor Building - Steel Framing Sections Revision O D 181 0 and Details 46 CEI Calculation 3.2.6.3, LOCA Doses as a Fundlon of Spray Initiation lime Revision 0 181 0 0 I 47 003.008-001-00, FSAR Figure 3.8-1, "Typical Section of Reador Building Revision 12 181 0 0 Complex."
48 NUS letter from A. E. Mitchell (NUS) to R. F. Zucker (CEI), CSA-8106187-12, N/A D D 181 PY-NUS/CEl-1474, dated 312198, "Habitability Chi/Os for Tse*. Attached to PNPP Cale 5.7.1.2, page 4. I 49 PNPP Calculation 5.7.1.2, Technical Support Center - Final Dose Revision 0 D D 181 50 PNPP Drawing E-013-011, Final Plant Layout, Section A-A Revisions D 181 D 51 PNPP Drawing E-002-002, Final Plant Layout, Section A Revision 15 D 181 0 52 PNPP Drawing D-912-610, Control Room HVAC and Emergency Recirculation Revision FF D 181 0 System 53 WASH-1400, "Reactor Safety Study: An Assessment of Accident Risks In U.S. 1975 181 D 0 Commercial Nuclear Power Plants,* NUREG 75/014, Nuclear Regulatory Commission, Washington, DC.
54 D.I. Chanin, J.L. Sprung, L.T. Ritchie, and H-N Jow, "Melear Accident 1990 181 D 0 Consequence Code System (MACCS) User's Guide,* NUREG/CR-4691, Vol. 1, Sandia National Laboratories, Albuquen::iue, NM.
NUREG/CR-6189, DA Powers et al, "A Simplified Model of Aerosol Removal 55 by Natural Processes in Reactor Containments." July 1996. 181 D 0
'5(o '?e~fN ~?ic lf'lc.. T6.CUHIC.AL Gu1~utJc K~V~oll to BJ D 0
'")'"1*1'1
Page 1 1.0 PURPOSE The purpose of this calculation is to prepare a dose analysis supporting the transition to GNF2 fuel and to establish the new design basis loss-of-coolant accident (LOCA) dose analysis. This calculation makes the current LOCA dose calculation (PSAT 08401T.03, DIN 25) and Technical Support Center calculation (Calculation 5.7.1.2, DIN 49) historical and removes certain conservatisms contained in the current LOCA d~se calculation to increase the margin of safety. This calculation will be performed in accordance with the guidance provided in Regulatory Guide 1.183 (DIN 7) for application of an alternative accident source term and will demonstrate that the offsite and onsite post-accident doses comply with the requirements and dose limits of 10 Code of Federal Regulations (CFR) Part 50.67 (DIN 14). Onsite doses calculated include the Technical Support Center (TSC) dose.
The evaluation of the limiting design basis loss-of-coolant accident will use the RADTRAD 3.03 Code Instead of the proprietary STARDOSE code used in PSAT 08401T.03. RADTRAD 3.03 was developed for the NRC and is commonly used in the nuclear power industry for applications of this type. Excess conservatisms removed from the current calculation (PSAT 08401T.03) are given In detail in the following sections and are summarized below:
- Increased Control Room Emergency Recirculation System (CRERS) charcoal filter efficiency for elemental and organic iodine from 50% to 80%.
- Credit for decay during the two (2) minute onset of the gap release.
- Credit for elemental and aerosol removal in the unsprayed containment region.
- Credit for reduced containment and annulus bypass leakage after 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> based on post-accident containment pressure.
- Increased CRERS HEPA filter efficiency from 95% to 99%.
An additional conservatism added to this calculation is the removal of credit for auto-initiation of the CRERS. Isolation of the normal ventilation system and actuation of CRERS is assumed to be performed manually from the control room at 30 minutes post-accident.
2.0 BACKGROUND
The Perry Nudear Power Plant (PNPP) pilot Alternative Source Term (ASn submittal to the NRC was based on the LOCA analysis presented in PSAT 08401T.03, Revision 5 (DIN 25). This analysis utilized the POLESTAR proprietary computer code STARDOSE to determine the offslte and onsite consequences of a LOCA.
The NRC, in approving the PNPP pilot Alternative Source Term (AST) submittal, performed a confirmatory radiological consequence calculation that evaluated potential fission product release pathways following a postulated LOCA. The NRC calculation was documented in the Perry Safety Evaluation by the Office of Nuclear Reactor Regulation related to Amendment No. 103 (DIN 1). The NRC staff used the RADTRAD Code.
Page2 The guidance of Regulatory Guide 1.183, uAltemative Radiological Source Terms for Evaluating Design Basis Accidents at Nuclear Power Reactors* (DIN 7), will be used to identify the conservatisms currently being applied in the Perry design basis LOCA model. Regulatory Guide (R.G.).1.183 establishes an acceptable Alternative Source Term (AST) and Identifies the significant attributes of other ASTs that may be found acceptable by the NRC staff. This guide also identifies acceptable radiological analysis assumptions for use In conjunction with the accepted AST. This calculation will remove some conservatism per the guidance of R.G. 1.183.
3.0 ACCEPTANCE CRITERIA The post-accident offsite and control room doses must meet the requirements of 10 CFR Part 50.67, uAccident Source Term.*
10 CFR 50.67 gives the limits applicable to plants revising their accident source terms. The dose limits specified are given in § 50.67. (b)(2)(i), (iO. and (iii) as follows:
(b)(2Xi)-An individual located at any point on the boundary of the exclusion area for any 2-hour period following the onset of the postulated fission product release, would not receive a radiation dose in excess of 0.25 Sv (25 rem) total effective dose equivalent (TEDE).
(bX2)(ii) - An individual located at any point on the outer boundary of the low population zone, who is exposed to the radioactive cloud resulting from the postulated fission product release (during the entire period of its passage), would not receive a radiation dose in excess of0.25 Sv (25 rem) total effective dose equivalent (TEDE).
(b)(2Xiii) -Adequate radiation protection is provided to permit access to and occupancy of the control room under accident conditions without personnel receiving radiation exposures in excess of0.05 Sv (5 rem) total effective dose equivalent (TEDE) for the duration of the accident For plants Implementing the alternative radiological source term methodology, the dose limits of 10 CFR 50.67, given above, replace the limits given In 10 CFR 100.11, uDetermination of exclusion area, low population zone, and population center distance;* which are expressed in terms of whole body and thyroid dose as follows:
(a)(l) An exclusion area of such siz.e that an individual located at any point on its boundary for two hours immediately following onset of the postulated fission product release would not receive a total radiation dose to the whole body in excess of 25 rem or a total radiation dose in excess of 300 rem to the thyroid from iodine exposure.
(aX2) A low population zone of such size that an individual located at any point on its outer boundary who is exposed to the radioactive cloud resulting from the postulated fission product release (during the entire period of its passage) would not receive a total radiation dose to the whole body in excess of 25 rem or a total radiation dose in excess of 300 rem to the thyroid from iodine exposure.
Page3 As noted above, the dose limit for control room personnel Is specified In 10 CFR Part 50.67 (DIN14).
4.0 METHOD OF ANALYSIS This calculation will evaluate the total effective dose equivalent (TEDE) for the PNPP design basis radiological accident (LOCA) using the revised accident source term based on Regulatory Guide 1.183, "Alternative Radiological Source Terms for Evaluating Design Basis Accidents at Nuclear Power Reactors* (DIN 7). The TEDE dose is defined as the sum of the deep-close equivalent (for external exposures) and the committed effective dose equivalent (for Internal exposures) (DIN 24). The RADTRAD Code, Version 3.03, will be used to calculate radiological consequences in terms of TEDE.
RADTRAD <Radionuclide Iransport and Removal .@nd Dose Estimation) calculates fission product transport and removal along with the resulting radiation doses at selected receptors. The code is described in NUREG/CR-6604, "A Simplified Model for Radionuclide Transport and Removal and Dose Estimation" (DIN 2, DIN 22, and DIN 23). RADTRAD 3.03 was certified for this application (DIN 30) in accordance with the ENERCON computer code certification procedure [ENERCON CSP 3.02].
5.0 ASSUMPTIONS 5.1 Control Room Emergency Reclrculatlon System (CRERS)
Upon receipt of an Engineered Safety Feature (ESF) actuation system signal or high radiation signal, the PNPP control room heating, ventilation, and air conditioning (HVAC) system is designed to automatically isolate and activate the CRERS; however, this analysis conservatively assumes that the normal HVAC system continues to operate with an outside air intake (6000 cfm+10% margin) and exhaust to the environment (4800 cfm) until the CRERS is manually actuated at 30 minutes.
Each redundant CRERS subsystem has a high efficiency particulate air (HEPA) filter, charcoal adsorbers and a post HEPA filter. Operation of the CRERS fans, charcoal adsorbers, and HEPA filters are credited in this analysis. The CRERS Is an ESF system that Is tested in accordance with R.G. 1.52 (DIN 20).
The current test acceptance criterion for the CRERS charcoal adsorbers requires a penetration of less than 2.5% (DIN 21). Based on the testing requirements, a charcoal adsorber removal efficiency of 95%
could be justified; however, for additional operational margin, elemental and organic Iodine removal efficiency is assumed to be 80%. Technical Specification 5.5.7 (DIN 21) states that each HEPA filter is tested to show a penetration and system bypass of less than 0.05% when tested in accordance *with Regulatory Guide 1. 52 (DIN 20). A penetration and bypass of less than 0.05% allows credit for a particulate removal efficiency of 99% per Regulatory Position C.5.c of Regulatory Guide 1.52. This analysis uses a HEPA filter efficiency of 99 percent for aerosol particulates.
5.2 Hydrogen Mixing System The hydrogen mixing system is manually initiated. For this analysis, operation of the hydrogen mixing system is not assumed. Due to the minimal (500 cfm) flow rate between the drywall and containment
Page4 there is little effect on drywell or containment radionuclide concentrations due to operation of this system.
Requiring operators to manually initiate the hydrogen mixing system early in the accident is not a good utilization of operator effort because of the minimal impact on accident doses.
5.3 Control Room lnleakage As described in Section 6.4 of the PNPP USAR (DIN 18), the control room is normally maintained at a slightly positive pressure to the surrounding areas from the 6600 cfm (includes a 10% tolerance on flow rate) fresh air makeup and out leakage of 4800 cfm. In the isolated mode, there is no intake from outside air sources and the control room pressure would eventually reach that of the surrounding areas. After the CRERS is initiated, the maximum control room unfiltered inleakage of 1375 cfm, will be used (DIN 11). The leakage out of the control room envelope is also modeled as 1375 cfm to avoid pressurization of the control room envelope.
5.4 Drywell Flows Leakage from the drywell into the primary containment is due to steaming from the heated reactor core in accordance with R.G. 1.183, Appendix A, Assumption 3. 7. This leakage is assumed during the two-hour period between the initial blowdown and termination of the fuel radioactivity release (gap and early in-vessel release phases). The termination of the release from the core is due to core recovery and reflood.
Instead of evaluating all of the potential steaming rates due to various reflooding scenarios, this analysis will assume that there is a homogenous mixture in the drywell and containment starting at two hours.
The assumption of a well-mixed drywall and containment atmosphere at two hours is appropriate because the EAB radiological doses consider the worst two hours as opposed to the first two hours as was done for the previous TIO 14844 source term methodology. The assumption of a well-mixed drywell and containment atmosphere is implemented by assuming a high mixing flow (2. nE+05 dm, approximately one drywell volume per minute) between the two volumes. The mixing flow is conservatively assumed to continue for the duration of the accident instead of isolating the drywall after the core is quenched.
The flow rate from the Drywell to the Wetwell, which bypasses the suppression pool, is given in PSAT 150.01C.03 (DIN 11, page 6) as follows:
Table 6-1 Drywall and Wetwell Mixing Flows Time After Gap Release Flow from OW to WW Flow from WW to DW (hours) (cfm) (cfm) 0-0.5 0 0 0.5-2.0 3000 0
Pages 2.0-720 2.77E+05 *2.77E+05 5.5 Containment Leakage Rate The primary containment consists of a drywell, a wetwell and supporting systems to limit fission product leakage during and following the postulated LOCA with rapid isolation of the containment boundary penetrations. The secondary containment will collect and retain fission product leakage from the primary containment and will release fission products to the environment through the Annulus Exhaust Gas Treatment System (AEGTS). During normal operation, the shield building is maintained at a slight negative pressure. Following a OBA, it is expected to remain negative, however for a short period it may not be maintained below the design negative pressure value of 0.25-inch. water gauge (USAR 6.5.3.2.1).
Therefore, it will be assumed that the primary containment leakage is released directly to the environment for the first 40 seconds following the LOCA (DINs 11 and 25). However, because the gap release does not begin until two minutes post-accident, this 40-second period when there may be direct release to the environment is not considered.
5.6 AEGTS Filtration The AEGTS includes HEPA filters which are periodically tested to demonstrate compliance with Regulatory Guide 1.52. Particulate removal by the HEPA filters is assumed to be 99% in accordance with Regulatory Guide 1.52 (DIN 20). The system also contains 4-inch deep activated charcoal adsorbers to remove elemental and organic iodine; however, this analysis conservatively assumes a removal efficiency of 0% for the charcoal adsorbers to allow operational flexibility.
The AEGTS extracts and filters a maximum of 2000 cfm from .the annulus. During an accident, the maximum expected discharge to the atmosphere is 1000 cfm (DIN 18). The balance of the filtered AEGTS flow is routed back to the annulus. This analysis conservatively assumes that 2000 cfm Is discharged directly to the environment with no recirculation (holdup) of iodine in the annulus.
5.7 Containment Spray Manual initiation of containment spray is assumed at thirty minutes instead of automatic initiation on high pressures and low water level per previous (DIN 25) analysis. Containment spray is assumed to end at 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> at which time the radionuclide removal by containment spray is terminated. USAR Subsection 6.5.2.3 gives a discussion of the non-mechanistic assumption that sprays will operate up to 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />. In an actual event, spray use would not necessarily be suspended at 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> if appropriate conditions for their use still existed. Therefore, the assumption that sprays stop at 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> is not intended to be interpreted as a commitment to stop using sprays after 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />. In addition, the statement that sprays will operate up to 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> implies that the sprays will not necessarily operate continually for 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />.
The containment sprays will be run when it is appropriate, and not necessarily the entire time during the first 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> of a LOCA. However, this does not invalidate the assumption used in this calculation. The
Pages accident guidance to operators is symptom based, rather than event based. Most postulated LOCAs will not result in large radiation releases and would not require containment sprays to run for 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> for removal of radioactivity from the containment. Sprays are also used to reduce containment pressure, as needed, by steam condensation and containment heat removal. If a high radiation signal is present from the containment radiation monitor and pressures are elevated in containment, the sprays would be operated. However, if containment gauge pressure is reduced to near zero and use of the sprays is terminated by the operators, this does not have an adverse impact on off-site doses (or the dose calculations) since the driving pressure for containment and main steam line leakage has been eliminated. The dose calculations assume that the maximum allowable leakage (la) corresponding to the peak post-accident pressure (Pa) remains during this first 24 hour2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> period, so If containment pressure is reduced to substantially less than Pa, a reduction in leakage and the resultant offsite doses will follow. If containment pressure increases again, and the high radiation signal is present, sprays would be actuated again.
5.8 ECCS Leakage Consistent with the previous analysis (DIN 25), this analysis assumes that the ECCS leakage is 15 gallons per hour (gph) for the entire duration of the accident. Additionally, leakage from a gross failure of a passive component is assumed to occur at a rate of 50 gallons per minute (gpm) starting 24 hour8 into the accident and lasting 30 minutes in accordance with NUREG-0800 SRP 15.6.5, Appendix B (DIN 44) :
Regulatory Guide 1.183, Appendix A, Section 5.2 states that engineered safeguards feature leakage should be assumed to start at the earliest time that recirculation flow occurs in these systems and end at the latest time the releases from these systems are terminated. For PNPP, ECCS leakage may begin up to 30 minutes post-accident but is assumed to begin at the onset of gap release at two minutes and continue for the duration of the event. This is a conservative assumption which maximizes the dose contribution for this release pathway.
5.9 l\'ISIV Leakage Rate There are four main steam lines; each line has an inboard MSIV, an outboard MSIV, and a third isolation (shutoff) valve. This analysis assumes a double guillotine pipe rupture in one of the four main steam lines upstream of the inboard MSIV and failure of all four third main steam shutoff valves (1N11-F0020A, B, C, and D) to close as a result of a common power failure (single-failure criterion). A total of a 250 scfh maximum allowable leakage limit (TS SR 3.6.1.3.10) is assumed to occur: (1) 100 scfh through the broken steam line, (2) 100 scfh through a second intact steam line, and (3) the remaining 50 scfh through a third Intact steam line. This is modeled as 100 scfh through the broken steam line and 150 scfh through the unbroken steam lines. The calculation converts this to non-standard conditions, as explained in more detail in Section 6.12, "MSIV Flows:
Page7 5.1 O Bypass Leakage A 'PoRllo.-.. of Secondary containment bypass leakage is iR afifiitieft ta the containment allowable leakage, La. The leakage paths include all pathways which could potentially allow leakage to bypass secondary containment. Therefore, any bypass leakage releases would not be treated by an ESF filtration system prior to being released to the environment. The secondary containment bypass leakage is currently limited to 5.04% of La. when pressurized to ~P., by Technical Specification SR 3.6.1.3.9 (DIN 15) even though the previous LOCA dose calculation (DIN 25) assumed a leakage of 10.08% of L8
- The containment bypass leakage will be maintained at 0.1008 La in this analysis to allow for an increase In the Technical Specifieation allowable leakage limit.
5.11 Source Tenn Release In accordance with R.G. 1.183 (DIN 7), only the gap and in-vessel release phases are considered in this design basis LOCA dose calculation. The core source terms are assumed to be released at a constant rate such that the release is completed by the end of the specified release period. Assumptions regarding release fractions and timing are consistent with Tables 1and4 of R.G. 1.183 (DIN 7).
Table 1 of R.G. 1.183 Is given below:
B'WR Core Inventory Fracdon Released Into Con&alnmeat
~~asJ :!~~
GroDPl P1ii9Pbase ~
Noble Gases 0.05 0.95 1.0 Halotzens 0.05 0.25 0.3 Alkali Metals 0.05 0.20 0.25 Telhui1101 Metals 0.00 0.05 0.05 Ba. Sr o.oo 0.02 o.oi Noble Metals 0.00 0.0025 0.0025 Ceri1un Group 0.00 0.0005 0.0005 Lanthanides o.oo 0.0002 0.0002 Table 4 of R.G. 1.183 Is reproduced below:
LOCA Release Phases PWRs BWRs Phase Onset Duration Onset Duration Gap Release 30 sec 0.5 hr 2 min O.Shr Early In-Vessel O.Shr 1.3 hr 0.5 tu* 15hr
Pages 6.0 Design Input 6.1 Plant Grade The PNPP plant grade elevation is 620 feet (DIN 50).
6.2 Core Source Terms and Releases The PNPP core source term release magnitude, timing and chemical form are based on Regulatory Guide 1.183 (DIN 7). The core source terms were developed by GE Hitachi (DIN 9). The calculated Inventories are based on 2-year GNF2 refueling cycles and serve as input for design basis accident analyses based on Regulatory Guide 1.183 source term assumptions. The fission* product inventory calculations were performed using the ORIGEN2 code. The Ci/MN multipliers developed In DIN 9 are applied here to generate the core source terms at the onset of the event. A reactor power level of 3833 MWt will be used based on 102% of the rated thermal power, 3758 MWt, as defined in Technical Specification 1.1, Definitions, page 1.0-5. Amendment 112 (DIN 15).
The GNF2 fuel source terms are based on the GNF2 equilibrium source activity given below. The source terms include fission products, actinides, and activation products. The listing of isotopes given In Table 6-1, below, is based on the isotopes used in the RADTRAD computer code. As stated in the RADTRAD User's Manual, NUREG/CR-6604 (DIN 2), the 60 isotope nuclide file is based on isotopes selected in WASH-1400 [DIN 53) with the addition of 6 Isotopes used in the MACCS code [DIN 54).
Table 6-1 Source Term GNF2 Equlllbrium lsotone fCllMWth)
Co58 2.647E+02 Co60 4.827E+02 Kr85 3.789E+o2 Kr85m 6.737E+o3 Kr87 1.283E+o4 Kr88 1.804E+04 Rb86 6.882E+01 Sr89 2.425E+04 Sr90 3.016E+03 Sr91 3.064E+04 Sr92 3.346E+04 Y90 3.118E+03 Y91 3.152E+04 Y92 3.362E+04 Y93 3.928E+04 Zr95 4.440E+04
Pages GNF2 Equfllbrfum Isotope fCllMWth)
Zr97 4.490E+o4 I Nb95 4.463E+o4 1*
Mo99 5.105E+04
- I Tc99m 4.470E+o4 Ru103 4.309E+o4 Ru105 3.046E+o4 Ru106 1.750E+04 Rh105 2.871E+o4 Sb127 3.016E+03 Sb129 8.906E+03 Te127 2.997E+03 Te127m 4.049E+02 Te129 8.762E+03 Te129m 1.304E+03 Te131m 3.965E+03 Te132 3.850E+o4 1131 2.714E+o4 1132 3.914E+o4 1133 5.495E+o4 1134 6.025E+o4 1135 5.150E+o4 Xe133 5.302E+o4 Xe135 1.934E+o4 Cs134 6.926E+03 Cs136 2.162E+03 Cs137 4.190E+03 Ba139 4.877E+04 Ba140 4.709E+o4 La140 5.002E+o4 La141 4.440E+o4 La142 4.278E+o4 Ce141 4.460E+o4 Ce143 4.090E+o4 Ce144 3.670E+o4 Pr143 3.957E+o4 Nd147 1.795E+o4 Np239 5.619E+05 Pu238 1.338E+02 Pu239 1.291E+01 Pu240 1.749E+01
Page10 GNF2 Equlllbrlum tsotoDe (CllMWth)
Pu241 5.748E+03 Am241 7.237E+OO Cm242 1.799E+03 Cm244 1.124E+02 6.2.1 Onset of Gap Release Table 4 of Regulatory Guide 1.183 tabulates values acceptable to the NRC for the onset and duration of each sequential release phase for OBA LOCAs at PWRs and BWRs. The specified onset of the gap
=
release Is the time following the initiation of the accident (i.e., time 0) prior to the start of the gap release. For a BWR the onset is 2 minutes. Credit will be taken for decay prior to the onset of the gap release at 2 minutes.
6.2.2 Release fractions The release fractions used in this analysis are consistent with Table 1 of R.G. 1.183 (DIN 7) which is reproduced in Section 5.11 of this calculation.
6.3 Suppression Pool Iodine Re-evolution The impact of any postulated iodine re-evolution from the suppression pool has been evaluated and shown to be negligible based on the pool pH level. If the pH is maintained above 7, very little (less than 1%) of the dissolved Iodine will be converted to elemental iodine (DIN 1, DIN 7). The Standby Liquid Control System (SLCS) is used for controlling and maintaining long-term suppression pool water pH levels to 7 or above. The pH of post-accident water in the containment will remain above 7 for the entire duration of the postulated LOCA (DIN 26). As such, this analysis will not consider any impad to the offsite or control room doses due to iodine re-evolution from the suppression pool. Also, in accordance With Appendix A of Regulatory Guide 1.183 (DIN 7), because the suppression pool pH is controlled at values of 7 or greater, the chemical form of radloiodlne released to the containment can be assumed to be 95% cesium Iodide (Csl), 4.85 percent elemental iodine, and 0.15 percent organic iodide.
6.4 Dose Conversion Factors The effective dose conversion factors for the TEDE calculations are based on FGR 11, "Limiting Values of Radionuclide Intake and Air Concentration and Dose Conversion Factors for Inhalation, Submersion, and Ingestion" (DIN 4) and FGR 12, "External Exposure to Radlonuclldes In Air, Water, and Soiin (DIN 5).
These reports tabulate dose coefficients for external exposure to photons and electrons emitted by radionuclides distributed in air, water, and soil, as well as, dose coefficients for the committed dose equivalent to tissues of the body per unit activity of inhaled or ingested radlonuclides. These dose coefficients for exposure to radiation are intended for the use in calculating the dose equivalent to organs and tissues of the body and are endorsed by the NRC in Regulatory Guide 1.183, Sections 4.1.2 (FGR
Page 11
- 11) and 4.1.4 (FGR 12). Dose conversion factors for the 60-isotope, 9 element NUREG 1465 {DIN 3) accident source term composition are included in the RADTRAD Input.
6.5 Atmospheric Dispersion Factors The atmospheric dispersion factors ('xjQ values) for the LPZ and EAB are obtained from PSAT 04202U.03 (DIN 13, page 10) and Calculation 3.2.6.3 (DIN 46). The Control Room atmospheric dispersion factors are documented in DES/98-845 (DIN 10). The Technical Support Center atmospheric dispersion factors are documented in PY-NUS/CEl-1474 (DIN 48) and Revision 0 of the TSC Dose Evaluation (DIN 49). The x/Q values, based on a ground level release, are given below:
Table&-3
'IJQ (seclm3 )
Location*
Time Interval EAB LPZ Oto 2 hrs 4.3E-4 4.8E-5 2to8hrs 4.8E-5 8to 24 hrs 3.3E-5 24to 96 hrs 1.4E-5 96to 720 hrs 4.1E-6 Table 6-4 Control Room and TSC 'IJQ (sec/m3 )
Time Interval CONTROL ROOM TSC Oto 8 hrs 3.5E-4 5.1E-5 8 to 24 hrs 2.1E-4 4.1E-5 24 to 96 hrs 1.1E-4 3.1E-5 96to720 hrs 5.75E-5 1.1E-5 6.6 Breathing Rate and Occupancy Factors The breathing rates applied in the calculation of the Inhalation dose are consistent with those reported In Sections 4.1.3 and 4.2.6 of R.G. 1.183 (DIN 7).
Table&-5 Breathing Rates (m3/s)
Time Period EAB LPZ Control Room/TSC Oto 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br /> 3.5E-4 3.5E-4 3.5E-4 Bto 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> 1.BE-4 1.8E-4 3.5E-4 1to30 days 2.3E-4 2.3E-4 3.5E-4
Page 12 The. control room and TSC occupancy factor$ are consistent with those reported in Section 4.2.6 of R.G.
1.183 and are tabulated below.
- Table 6-6 Control Room and TSC Occupancy Factors Time Period Occupancy Factor Oto 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> 1.0 1 to4 days 0.6 4to30 days 0.4 6.7 Containment Volumes The volumes of the containment regions are from CEI Calculation 3.2.6.4, Revision 0, Page 3A of 33 (DIN 31).
Table 6*7 Containment Volumes Region Volume (ft"')
Unsprayed Containment 684,226 Sprayed Containment 481,174 Drywall 276~500 Note: the above volumes are shown as rounded values in the RADTRAD screen views but the actual values are used in the RADTRAD input file.
6.8 Technical Support Center Doses Doses to personnel in the Technical Support Center (TSC) are calculated in the same manner as the doses to the Control Room operators except for the TSC specific atmospheric dispersion, xfQ, values and TSC data. The additional data needed to determine the TSC doses is as follows (DIN 49, page 9 and 10, and DI 5.7.1 page 18):
Table&-8 TSCData Parameter Value TSC Volume (ff) 113,412 HVAC Flow Rate (cfm) 37,000 Recirculation Filter Flow Rate (cfm) 6,000 Charcoal Filter Bed Depth (in) 2 Filtered Damper lnleakage (cfm)* 12 Unfiltered lnleakage (cfm)** 27.2
- Added to unfiltered inleakage
Page 13
- After recirculation is initiated at 60 minutes (includes 1O cfm for ingress and egress)
For the TSC charcoal removal efficiency, a removal efficiency of 80% will be used to provide margin as was done for the Control Room charcoal adsorber removal efficiency. Note that in the RADTRAD files, the TSC is labeled as the Control Room. The normal HVAC flow is assumed to operate for the first 60 minutes after which It is isolated and the recirculation filter is initiated.
6.9 Mixing Between the Unsprayed Containment and Sprayed Containm~nt The mixing rate between the unsprayed containment and the sprayed containment was determined to be 71,400 dm in Calculation PSAT 04202U.03, Rev. 0 (DIN 13, page 6).
6.1 O Containment Leakrate The maximum allowable primary containment leakrate, La, is 0.2 volume percent per day at the peak containment pressure (Pa) of7.80 psig per Technical Specification 5.5.12 (DIN 15). Per Assumption 5.5, primary containment leakage is released directly to the environment for the first 40 seconds following the LOCA, when the shield building may not be at a negativ_e pressure. This potential 40 second release directly to the environment is not modeled because it has no dose significance. Following this 40-second period, the annulus will collect and retain any fission produd leakage from the primary containment and will release fission products to the environment through the AEGTS. Secondary Containment Bypass leakage is a portion of the total containment leakage, La. Technical Specification SR 3.6.1.3.9 (DIN 15) limits the secondary containment bypass leakage to equal to or less than 5.04 percent of the primary containment leak rate. The containment bypass leakage for this calculation Is assumed to be 0.1008 La.
(Assumption 5.10)
Therefore, the leakrate for the sprayed and unsprayed (including drywell) regions of the containment is calculated below:
- [(4.812e + 05 ft 3 )
- 0.2%]
Leakrate from Sprayed Region = min 24hr
- 60liT Leakrate from Sprayed Region = 0.668 cfm Subtracting the bypass leakage of 0.1008*La (i.e., 0.067 dm) gives:
Leakrate from Sprayed to Annulus = 0.668 - 0.067 cfm = 0.601 cfm
[(6.842e + 05 ft 3 + 2.765e + 05 ft 3 )
- 0.2%]
Leakrate f ram Unsprayed Regions = min 24hr*60rr
Page 14 Leakrate from Unsprayed Regions = 1.334 cfm Subtracting the bypass leakage of 0.1008*La (i.e., 0.134 cfm) gives:
Leakrate from Unsprayed Regions to Annulus = 1.334 - 0.134 cfm =. 1.2 cfm Bypass Leakage:
Sprayed Region Bypass Leakage = 0.668 cfm
- 0.1008 = 0.067 cfm Usprayed Regions Bypass Leakage= 1.334 cfm
- 0.1008 = 0.134 cfm Total Bypass Leakage = 0.202 cfm Table6-9 Containment Leakrate Summary Leakrate (W/mln)
Leakage 'IO sec. to 24 hrs From Sprayed Region to Annulus 0.601 From Unsprayed Regions to Annulus 1.2 Bypass Sprayed Region to Environment 0.067 Bypass Unsprayed Regions to Environment 0.135 (rounded up) 6.11 Leakage after 24 Hours Containment leakage depends upon containment pressure and will be reduced at 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> as allowed by Regulatory Gulde 1.183, Appendix A, Section 3. 7. Based on the post-accident containment pressure curve for a MSLB (DIN 27), the containment pressure at 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> post-accident is 18.1 psia. This value was obtained by digitizing the containment pressure curve and finding the pressure at 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />.
Atmospheric pressure at the elevation of the PNPP site (620 ft AMSL) is 14.37 psia. Because the flow rate is proportional to the square root of the differential pressure, the reduction in flow rate may be estimated as follows (assuming all other parameters remain constant):
./IB~4.37 =0.691=>0.69 7.8
Page 15 Because the secondary containment bypass leakage also depends upon containment pressure, this leakage rate will also be reduced to 69% of the pre- 24 hour2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> values beginning 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> post-accident.
Therefore, this analysis will reduce all leakage flows to 69% of the Df!f-24 hour value after 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />.
Table 6-10 <p1,j. Jw tJ./, *t'(
Containment Leakrate after 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> Leakage Leakrate (tr/min)
From Sprayed Region to Annulus 0.415 From Unsprayed Regions to Annulus 0.828 Bypass Sprayed Region to Environment 0.0462 Bypass Unsprayed Regions to Environment 0.0932 6.12 MSIV Flows The flows given in Section 5.9 are based on MSIV leakage rate testing requirements at standard conditions. The drywell atmosphere will not be at standard conditions after the reactor blowdown.
Calculation PSAT 04202H-04 (DIN 12, page A3) determined that the total MSIV flow rate from 0 to 7484 seconds was 298 cfh based on the minimum post-accident drywell pressure of 15. 7 psia and minimum temperature of 215°F. From 7484 to 86400 seconds, the MSIV flow rate Is 247 cfh based on the minimum pressure of 15.7 psia and temperature of 100°F.
Based on the assumed flow split given in Section 5.9, the flow through the broken steam line is:
298 cfh 100 scfh Qbroken uneCt S 7484 seconds) = min/hr* 250 scfh = 1.987 cfm 60 247 cfh 100 scfh Qbroken uneC7484 < t :5 86400 seconds) = 60 min/hr* 250 scfh = 1.647 cfm The flow through the intact steam lines (100 scfh through a second intact steam line and the remaining 50 scfh through a third Intact steam line) is given below.
- 298 cfh 150 scfh Qintactlines(t S 7484 seconds) = 60 min/hr* 250 scfh = 2.98 cfm 247 cfh 150 scfh QfntactUnesC7484 < t S 86400 seconds)= min/hr* 250 scfh = 2.47 cfm 60
Page 16 Consistent with Section 6.2 of Appendix A to R. G. 1.183, this leak rate may be reduced by as much as a factor of 2 after 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />, if supported by plant specific analysis. As calculated above, this analysis will reduce all initial leakage flows to 69% of the pre-24 hour. leak rate after 24 hrs. This leakrate is conservatively based on the Initial flows (i.e., t<7484 seconds). The MSIV leakage flows at this time become:
Table 6-11 Steam Line Leakrate after 24 Hours Leakage Path Leakrate (ff/min)
Broken Steam Line 1.371 Intact Steam Lines 2.056 The main steam line leakage rate is required to be less than or equal to 100 scfh (Technical Specification SR 3.6.1.3.10) when tested at Pa (7.80 psig). The test temperature is assumed to be 70°F and the RCS operating temperature is 552°F (saturated temperature at steam dome pressure of 1045 psig, LCO 3.4.12). Converting the 100 scfh leakage rate to operating temperature gives a leakage rate of 191 cfh.
The MSIV flow after the first piping segment from the drywell will be based on a constant maximum steam line flow of 191 dh (3.183 cfm) (DIN 11, page 8) for the broken steam line and 191 cfh*150
=
scfh/100 scfh 4. 775 cfm for the unbroken lines. No reduction in flow at 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> for these *line segments will be taken. This conservative model is unchanged from the previous analysis (DIN 25).
6.13 Radionuclide Removal Mechanisms Removal mechanisms for elemental iodine and aerosols will be applied in this calculation using NRC correlations incorporated into the RADTRAD 3.03 code.
6.13.1 Removal by Deposition Elemental Iodine Removal by Deposition Elemental iodine removal is credited in the drywell and containment volumes. Airborne elemental iodine is removed by deposition to the walls in the drywell and containment. As reported in Section 5.1.2 of NUREG/CR-0009, DIN 33), this process is driven by the temperature differences between the surfaces and the atmosphere. The removal factor reported in NUREG/CR-0009 is given by the following equation .
.ii.= K9 A v
where:
=
1i. removal rate constant due to surface deposition, kg= average mass transfer coefficient 0.137 cm/s (16.18 ft/hr) from page 17 of NUREG/CR-0009,
Page 17 A =surface area for wall deposition, and V =volume of contained gas.
This formula is also reported in Standard Review Plan 6:5.2 (DIN 34) as a method of calculating the total elemental iodine removal capability. These removal constants are applied until a decontamination factor
{OF) of 200 has been obtained.
Volume and Area Calculations Drvwell Volume For all volume calculations, surfaces other than the inner and outer building wall will be conservatively neglected. The PNPP drywell volume of 276,500 ft3 from CEI Calculation 3.2.6.4, Revision 0, Page 3A of 33 (DIN 31) is used in this calculation.
Wall Surface Area Considering the 36'6" inside radius (DIN 45) of the drywell cylinder and the approximately 66 foot height above the suppression pool high water level (DIN 51), the area of the inner drywall wall is calculated to be 16.000 ft2. The use of the suppression pool high water level is conservative because it minimizes the wall surface area available for deposition.
Area = rrDh = rr
- 73'
- 66' = 15136.2 f t 2 or, 15,000 /t 2 Sprayed Containment Region Volume Although in some parts of the containment, the containment spray would fall directly to the suppression pool, the refueling floor {grating) at El. 689'-6" would affect a large fraction of the containment spray. As such, the only containment volume credited with spray removal is that area above the refueling floor. The upper containment (sprayed) region volume of 481, 174 ft3 from CEI Calculation 3.2.6.4, Revision 0, Page 3A of 33 (DIN 31) is used in this calculation.
Wall Surface Area The surface area is taken as the containment wall area above the refueling floor at 689'-6" (DIN 47) and below the containment spring line at 727' (DIN 47). Using the containment radius of 60' (DIN 45) the surface area is calculated below as 14, 137 ft2.
Area = rrDh = rr
- 2
- 60' * (727' - 689.5') = 14,137 /t 2
Page18 The surface area of the oblate elliptical spheroid above the spring line is given by: (DIN 32) c 2
S = 2na2 + 11- ln - -
- (1 + e) e 1-e Where "a" is the equatorial radius and *c" is the polar radius and the ellipticity, "e" is given by:
e=V ~1-az Substituting 60' for "a" and (757' - 727' = 30') for uc" {DIN 47) gives:
e= (30') 2 1- (60')2 =0.866 2
S -- 2n * (60)
, 2
+ 11 (30')
_ ln (1 + _ 0.866)
_ -- 31,218 ft 2 0 866 1 0 866 The surface area of the dome is half of this total area: S =31,218 ft!-12 =15,609 ft!-
The total area available for plateout is therefore 29,746 ft!- or, 29,000 ft!-.
Unsprayed Containment Region Volume The volume of the unsprayed containment region is 684,226 ft3 per from CEI Calculation 3.2.6.4, Revision 0, Page 3A of 33 {DIN 31).
Wall Surface Area Considering the 41 '6" outside radius of the drywall {DIN 45) and the approximately 96 foot height (689' -6"
- 593'-4" = 96.17') above the suppression pool high water level {DIN 51), the area of the outside drywall wall is calculated to be 25,000 ft2. The use of the suppression pool high water level is conservative because it minimizes the wall surface area available for deposition.
Page 19 Area= nDh = 7r
- 2
- 41.5'
- 96' = 25,032 ft 2 or, 25,000 /t2
- The radius of the unsprayed containment wall is 60' gMng a surface area of Area = nDh = n
- 2
- 60'
- 96' = 36,191 f t 2 or; 36,ooo /t 2 This gives a total surface area of 61,000 ft3 Using the above wall areas and volumes, the removal rate constants are given below:
Table 6-12 Elemental Iodine Deposition Removal Factors Removal Volume Wall Area Factor Node (tt3) (ft2) (h1"1)
Drywell 276,500 15,000 0.878 Sprayed Containment 481,174 29,000 0.975 Unsprayed Containment 684,226 61,000 1.443 Airborne elemental iodine removal by deposition to the walls In the drywell and containment is assumed to end when a OF of 200 is reached.
Aerosol (particulate) Removal by Deoosltlon Regulatory Guide 1.183, Appendix A, Section 3.2 (DIN 7), discusses the reduction in airborne radioactivity in the containment by natural deposition. This section references the model in NUREG/CR-6189 (DIN 55) as an acceptable model. This model (the "Powers* model) Is Incorporated Into the RADTRAD code. Aerosol removal in the drywell and unsprayed containment region Is based on the 10%
Powers Aerosol model in RADTRAD. Note that, for unsprayed regions, the reactor and accident type used in the Powers aerosol model must be reset to *eWR-Deslgn Basis Accident" prior to each execution of the RADTRAD code.
6.13.2 Removal by Sprays Aerosol Removal by Sprays A simplified model for estimating the fission product aerosol removal by containment sprays following a postulated LOCA is used. The model for aerosol removal by sprays built into the RADTRAD 3.03 code is the Powers model. The model was developed using values of 10, 100, and 2500 cm3 H20/ cm2-s for the spray water flux. The model should not be used for spray water fluxes and fall heights outside of these
Page20 ranges (DIN 2, 22, and 23). The Powers model was derived by correlating the results of Monte Carto uncertainty sampling analyses assessing the uncertainties in aerosol properties, aerosol behavior, spray droplet behavior, and the Initial and boundary conditions expected to be associated with a postulated LOCA in the containment. The Powers mechanistic model requires that the user specify the following:
- 1. Q, the spray water flux, in cfmlsq ft;
- 2. H, the fall height, in meters:
- 3. ALPHA, the ratio of unsprayed volume to sprayed volume,
- 4. PCT, the uncertainty percentile selected for the model (10th, Soth, 90th percentiles).
=
The spray alpha is 6.8423E+05/4.8117E+05 1.422. The other two parameters used in this evaluation that are not treated as uncertainty distributions for Perry are (1) spray water flux, and (2) mean spray fall height. These parameters are specified based on plant specific design information. The ubest estimate" value is associated with the 50th percentile; or median values: the lower bound Is associated with the 10th percentile; and the reasonable upper bound, or largest decontamination factor (DF), with the 90th percentile. For aerosol removal by containment spray, the RADTRAD Powers Model 10th percentile uncertainty distribution for fission product in aerosol form is used in this analysis. Note that the reactor and accident type used in the Powers aerosol model must be reset to "BWR-Design Basis Accidenr prior to each execution of the RADTRAD code.
The PNPP LOCA dose analysis credits spray removal of aerosols in the sprayed region of the containment. The Powers spray removal model implemented in RADTRAD requires the spray flux and spray height as inputs. The spray flow is 5250 gpm (D-302-0661-00000, Rev. G, DIN 35) per train.
Technical Specification 3.6.1. 7 requires that the spray flow from the RHR system be ~5250 gpm.
Because the Powers model spray removal is a direct function of spray flow rate, a lower bound of the spray flow (i.e., 5250 gpm) Is conservative.
. _ Spray Flow _ 5250 gpm
- 0.1337 cfm/gpm _ cfm/
Spray Flux - Sprayed Area - n * (60')2 - O.O 620 6 sq ft The average droplet fall height is dependent on the available train of containment spray. As shown below, the headers for the "N Train are located above the headers for the "B" Train per* drawing D-320-0661-00000, Rev. G. If the flow rate through all nozzles is assumed to be equal, the average drop height can be calculated by the nozzle-weighted average of the drop heights. The average drop height is used because the train operating post-accident is unknown. The drop height is based on the distance above the operating floor at El. 689'-6" (DIN 51).
Page21 Table 6-13 PNPP Containment Spray Heights RHR Header Header Refe19nce Drawing Height* H1 Number of Ni*HI Train 7 Designation Elevation (ft) Nozzles - N1 (ft)
A A 735.250 D-314-661, Sheet 3, 45.75 129 5901.75 Rev. 8. fDIN 36l c 744.250 SS-304-661, Sheet 54.75 113 6186.75 105.2, Rev. C, (DIN 38)
E 750.500 SS-304-661, Sheet 61.00 102 6222 102.2, Rev. B, (DIN 40)
B B 737.000 0-314-661, Sheet 8, 47.50 129 6127.5 Rev. B, tDIN 37l D 745.750 0-314-661, Sheet7, 56.25 113 6356.25 Rev. B. COIN 39)
F 752.000 D-314-e61, Sheet 6, 62.50 104 6500 Rev. B, COIN No. 41)
,_T.;..;o-.,;ta-.,1_ _._..;6;;...;.9.;;..0_ _ _ _ 37294.25 7
I Average {ft) 154.05 I 320-0661-00000, Rev. G (DIN 35) where:
N1Is the number of nozzles on header I His the height of header i above the operating floor (ft)
The average fall height for both trains combined is therefore 64.06 ft.
As discussed in SRP 6.5.2 (DIN 34), because the removal of particulate material depends markedly upon the relative sizes of the particles and the spray drops, the aerosol spray removal lambda is assumed to decrease by a fader of 10 after the aerosol mass has been depleted by a fader *af 50.
Page22 Elemental Iodine Removal bv Spravs SRP 6.5.2 provides guidance on calculating the spray lambda for removal of elemental iodine. The following formula is valid for lambdas greater than 10 per hour with a maximum of 20 per hour to prevent extrapolation beyond the existing data.
where:
As= first-order removal coefficient by spray,
=
kg the gas-phase mass-transfer coefficient,
=
T the fall time of the drops, which may be estimated by the ratio of the average fall height to the terminal velocity of the mass-mean drop,
=
F volume flow rate of the spray pump,
=
V containment building net free volume, and
=
D mass-mean diameter of the spray drops.
Gas Phase Mass Transfer Coefficient The gas-phase mass-transfer coefficient, kg, can be determined by back-calculation from a solved case with slightly different assumptions. Specifically, the example on Page 106 of NUREG/CR-0009, "Technological Bases for Models of Spray Washout of Airborne Contaminants in Containment Vesselsn, 1978, (DIN 33) uses the stagnant film model to determine the spray removal coefficient for a PWR case with a 1713 spray nozzle and the following parameters.
As= 14.2 hr"1
=
F 1500gpm V =1.75E6 ft3
=
Height 90 ft Temp= 250°F Solving the above equation for kg, gives:
A5 *V*D kg= 6*T*F To calculate kg, the values of the mass-mean drop diameter, D, and the fall time of the drops, T, are needed. The PNPP spray nozzles are Spraco 1713A nozzles (DIN 35). Recent test results with the Spraco 1713A nozzles presented in Figure 4 of NUREG/CR-5966 (DIN 6) have a mean droplet size of 234 1Jm (NUREG/CR-5966, page 7) and an upper diameter of about 1500 1Jm. The mass-weighted average drop size, however, will be larger than 234 microns since the larger drops have exponentially more mass. This volume-weighted size distribution (which is directly related to the mass-weighted distribution) is reported in Figure 7 of NUREG/CR-5966 which Illustrates an average of the volume
Page23 weighted distribution to be approximately 1200 microns. A value of 1200 microns will be applied in this calculation. The terminal velocity of 1200 µm drops can be found to be approximately 400 cm/s from Figure 16 of NUREG/CR-5966. Conservatively assuming the velocity Is equal to the tenninal velocity, a 90 foot (2743 cm) fall height gives a fall time of 6.86 seconds. Using the above data to determine the gas-phase mass-transfer coefficient, kg, gives:
As* v
- D 14.2hr- 1 60h~in*1.75E6ft 3 *1200*10- 6 m
- loocm/m cm kg = 6*T
- F = _90 ft cm 6
- 400 cm/sec* 30.4Bir
- 1500 gpm
- 0.1337 iii ft: 3 = 6 sec For PNPP, the average fall height of the spray drops is calculated to be 54.05 ft (1647 cm). The terminal velocity of 1200 tJm drops can be found to be approximately 400 emfs from Figure 16 of NUREG/CR-5966. The drop fall time is calculated to be 4.1 seconds. The spray flow is 5250 gpm from D-302-0661-00000, Rev. G, (DIN 35) and the sprayed volume of the containment is 481, 174 fl3 from CEI Calculation 3.2.6.4, Revision 0, page 3A of 33 (DIN 31). From the SRP equation, below, the PNPP spray lambda for elemental iodine can be calculated to be 107.66 hr.
cm ft: 3 min 6 *kg
- T
- F 6
- 6sec
- 4.1sec*5250 gpm
- 0.1337 gal* 60nr _ _
1 107 66
.ils = V* D = 481,174 ft:3
- 1200
- l0-6 m .10ocm/m -
- hr This result is reasonable considering the 14.2 hr1 value calculated for the PWR case described in NUREG/CR-0009, the much higher spray flow rate at PNPP, and the smaller sprayed volume at PNPP.
Since the SRP allows a maximum lambda of 20 hr"1, this calculation will apply a spray removal lambda of 20 hr"1 for elemental iodine. As discussed previously, elemental iodine is removed by deposition to the walls in the containment with a removal coefficient of 0.975 hr"1 for the sprayed region which gives a total elemental iodine removal coefficient for the sprayed region of containment as 20.975 hr1* As discussed in SRP 6.5.2, the maximum decontamination factor is 200 for elemental iodine. The effectiveness of the spray in removing elemental iodine will be presumed to end at that time, post-LOCA, When the maximum elemental iodine OF is reached.
Page24 6.14 Annulus Model The Annulus Exhaust Gas Treatment System (AEGTS) Is an engineered safety features system designed to collect, process, and release the fission product leakage from the primary containment into the shield building. *The system is operated continuously during normal operation and maintains a slight negative pressure In the shield building. The AEGTS is a redundant system consisting of pre-HEPA filters, charcoal adsorbers and post-HEPA filters. ~eduction in release activity by ESF ventilation filtration systems may be credited where applicable if filter systems used in these applications are evaluated against the guidance of Regulatory Guide 1.52 (DIN 20). The AEGTS charcoal adsorbers are not credited for reducing the released activity, so testing in accordance with R.G. 1.52 is not necessary.
The AEGTS HEPA filter is tested in accordance with Regulatory Guide 1.52 to verify a penetration and system bypass of less than 0.05% (DIN 21). Aerosol removal by the HEPA filters is therefore assumed to be 99%. As discussed previously, no credit for charcoal filtration of the annulus exhaust is taken in this .
calculation.
6.15 Deposition In Main Steam Lines The deposition in the main steam lines will use the aerosol removal efficiencies from PSAT 08401T.03 (DIN 25) which was based on PSAT 04202H.08 (DIN 42). These removal efficiencies include a 10%
increase in aerosol penetration to add conservatism to the main steam line leakage pathway. The removal efficiencies are given below.
Table 6-14 Main Steam Line Removal Fractions Time after MSL 1 MSL2 MSL3 release (hr) (failed steamline) (pipe to intact steamlines) (intact steamlines) 0.0 0.681 0.7206 0.714 0.5 0.835 0.7206 0.813 1.5 0.8713 0.7206 0.8361 3.0 0.89 0.7206 0.8449 5.0 0.8614 0.7206 0.8339 7.0 0.8185 0.7206 0.7998 9.0 0.769 0.7206 0.7558 11.0 0.3653 0.7206 0.3807 720 0.0 0.0 0.0 The elemental iodine removal efficiency is 0.45 for all steam lines (DIN 25).
Page25 7.0 ACCIDENT SCENARIO AND CHRONOLOGY 0 minutes to 2 minutes A design basis double-ended guillotine break occurs in a main steam line upstream of the inboard MSIV, releasing reactor coolant into the drywall. The drywell ls pressurized driving drywell atmosphere out the MSIVs and into containment via the drywell bypass. All MSIV and containment leakage is Initially directed to the environment. The AEGTS system achieves a 0.25-inch vacuum in the secondary containment at 40 seconds (Assumption 5.5) and draws 2000 cfm of secondary containment atmosphere through a HEPA filter and charcoal bed before release to the environment. Because there Is no core damage during this 40 second drawdown period, it is not included In the RADTRAD model. Following this drawdown period, all primary containment leakage is directed to the secondary containment except for the containment bypass leakage, which _is assumed to bypass secondary containment and is released directly to the environment. No credit for elemental or organic iodine removal by the AEGTS charcoal adsorbers is taken. Particulate removal by the HEPA filters is assumed to be 99% in accordance with Regulatory Guide 1.52. The control room and offsite dose points begin to accumulate dose from the ECCS, MSIV and containment leakage. The control room normal ventilation mode is assumed to continue until the CRERS is manually initiated at 30 minutes.
2 minutes to 32 minutes
- The gap release begins by releasing the gap source terms into the drywall at a constant rate over the 30-minute release period following the onset of gap release at two minutes post-accident ECCS leakage is assumed to begin at this time leaking contaminated suppression pool water (10% of iodine - all forms) directly to the environment even though the postulated core damage is occurring because no ECCS injeciion Is assumed to be available during the first two hours. The control room and offslte dose points begin to accumulate dose from the ECCS, MSIV and containment leakage. At 30 minutes post-accident, the control room normal ventilation system is manually isolated, and the CRERS is manually initiated.
The CRERS fans recycle 27,000 cfm of control room atmosphere through HEPA filters and charcoal adsorbers. Manual initiation of containment spray is assumed at thirty minutes. Manual initiation of containment spray at 30 minutes is reasonable based on Emergency Operating Procedure guidance f D*
requiring operation of containment spray based on the "Pressure Suppression Pressure" curve contained in the EOP. The containment pressure threshold is met within 30 seconds of the LOCA per DIN 27.
32 minutes to 122 minutes At 30 minutes, the control room normal ventilation system is manually Isolated, and the CRERS is manually initiated. The CRERS fans recycle 27,000 cfm of control room atmosphere through HEPA filters and charcoal adsorbers. The in-vessel release begins at 30 minutes after the onset of gap release
Page26 by releasing the in-vessel source terms into the drywall at a constant rate over a 90-minute release period. Manual* initiation of containment spray is assumed at thirty minutes. Manual Initiation of containment spray at 30 minutes is reasonable based on Emergency Operating Procedure guidance requiring opera~ion of containment spray based on the "Pressure Suppression Pressure* curve contained in the EOP. The containment pressure threshold is met within 30 seconds of the LOCA per DIN 27.
122 minutes to 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> The source term release from the vessel is terminated at 2 hours2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br /> after the onset of gap release with the actuation of ECCS, which results in large amounts of steam evolution and large flows out of the drywall into the containment. The drywall and lower containment region are assumed to become well-mixed at 2 hours2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br />./ ,A,. ,.1.1* 1'f
- 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> to 30 days Releases to the environment via the containment bypass, MSIV leakage, ECCS leakage and AEGTS exhaust continue for 30 days. As discussed above, containment leakage is reduced at 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> based on containment pressure.
8.0 MODEL DEVELOPMENT This analysis considers the following three pathways through which source terms can be released from the containment
- . ECCS liquid leakage outside of containment
- MSIV leakage
- Containment airborne leakage (containment bypass and containment leakage)
These three pathways are discussed below. RADTRAD modeling capabilities allow incorporation of the MSIV leakage and the containment airbome leakage into one model, therefore; the three release pathways are addressed In two RADTRAD models.
8.1 ECCS Liquid Leakage 8.1.1 Source Tenns The gap and core activity is released to the drywell atmosphere based on the release fractions and timing reported in Tables 1 and 4 of R. G. 1.183 and is assumed to be immediately dissolved in the suppression pool. Only halogens are modeled In this analysis. Noble gases are not soluble and, with the exception of Iodine, all other radioactive materials in the recirculating liquid should be assumed to be retained in the liquid phase. This is consistent with the guidance of R.G. 1.183, Appendix A.
Page27 8.1.2 Volumes The suppression pool inventory expected during the LOCA is 114,379 ft3 (DIN 11). No credit Is taken for holdup in the Auxiliary Building where the ECCS systems are located.
8.1.3 Flows The earliest that the containment spray system could potentially be automatically initiated to spray the Containment is 10 minutes post-accident if high containment pressure combined with other LOCA signals is sensed. For this calculation it is conservatively assumed that the ECCS system leakage begins immediately after the LOCA (at the beginning of the gap release at two minutes post-accident).
Consistent with the previous analysis (DIN 25), this analysis assumes that the ECCS leakage is 15 gph (0.0334 cfm) for the entire duration of the accident. This Is twice the established administrative limit of 7.5 gph. Additionally, *leakage from a gross failure of a passive component is assumed to occur at a rate of 50 gpm (6.68 cfnl) starting 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> into the accident and lasting 30 minutes in accordance with NUREG-0800 (DIN 44).
8.1.4 Removal Mechanisms Because the suppression pool temperature will not exceed 212°F (DIN 11) during the accident, ten percent of the iodine in the ECCS leakage is assumed to become airbome consistent with R.G. 1.183, Appendix A. Natural removal mechanisms and holdup In the auxiliary building are conservatively neglected. Consistent with Section 5.6 of R.G. 1.183, Appendix A, the chemical species of these airborne source terms Is assumed to be 97% elemental and 3% organic.
8.1.5 Model The ECCS liquid leakage model is Illustrated in Figure 1.
8.1.6 Results The radiological doses for the ECCS liquid leakage transport path are reported in Table 11-1. The RADTRAD output file, Including the input summary, is listed in Attachment 1.
8.2 MSIV Leakage 8.2.1 Source Tenns As discussed previously, the PNPP core source terms have been developed with the ORIGEN2 methodology. These source terms are released into the drywell based on the release fractions and timing reported in Tables 1 and 4 of R.G. 1.183.
Page28 8.2.2 Volumes This analysis assumes a double guillotine pipe rupture in one of the four main steam lines upstream of the inboard MSIV and failure of all four main steam shutoff valves (1 N11-F0020A, B, C, and D) valves to close as a result of a common power failure (single-failure criterion). The maximum allowable MSIV leakage of 250 scfh ls modeled to occur through two pathways: (1) through the broken steam line and, (2) through the second and third intact steam lines. The volume of the ruptured main steam line between the MSIVs is 146 ft3 (DIN 11). Leakage past the second MSIV in this line is released directly to the environment. The volume of the two intact steam lines between the reactor vessel and the inboard MSIVs is 440 ft3 (DIN 25). The leakage past the first MSIVs in these lines is released to the volume between the first and second MSIVs which Is 292 ft3, two times the volume between the MSIVs In one steam line (146 ft3) (DIN 11). Leakage past the second MSIVs In these lines is also released directly to
- the environment. This configuration was previously identified in DIN 17 to be limiting with respect to dose consequences.
8.2.3 Flows This calculation will apply a maximum MSIV leak rate of 250 scfh with the worst-case main steam line leaking no more than 100 scfh. The leakage limit is assumed to occur: (1) 100 scfh through the broken steam line, (2) 100 scfh through a second intact steam line, and (3) the remaining 50 scfh through a third intact steam line. As stated above, leakage is modeled to occur through two paths, one path consisting of the broken steam line and a second path consisting of the second and third Intact steam lines. All leakage past the outboard MSIVs is assumed to be released to the environment.
The drywell atmosphere will not be at standard conditions after the reactor blowdown. The MSIV leakage rate must be.converted to a flow at the drywell conditions. The MSIV leakage rates at the drywell conditions were determined from PSAT 04202H.04 Rev. 0 (DIN 12). The leakage rates are reduced at 2 hours2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br /> when well-mixed conditions between the drywell and primary containment apply.
Additionally, the flow In the main steam lines past the Inboard MSIV is represented as well-mixed. The total MSIV leakage rates (DIN 1 and 11) are 298 cfh for the first two hours and 247 cfh thereafter. The maximum flow rate is 191 cfh (DIN 11) through any single main steam line to the environment. The values used in the model are given in Section 6.12.
In addition to the leakage through the MSIVs, the drywell will also continue to leak activity Into the containment over this 2 hour2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br /> period. This calculation will assume a leakage rate of 3000 cfm for the drywell bypass flow consistent with PSAT 08401T.03 (DIN 25).
8.2.4 Release Points All MSIV leakage past the outboard MSIV is assumed to be released directly to the environment. No credit for holdup in the auxiliary building or turbine building is taken.
Page29 8.2.5 Model The RADTRAD model applied for this leakage path, as well as the containment airborne leakage path, Is illustrated in Figure 2.
8.3 Containment & Containment Bypass Leakage 8.3.1
- Volumes In addition to the main steam lines, the following volumes are used in the LOCA airborne leakage dose calculation (DIN 11 and DIN 31):
Table 8-2 LOCA Volumes Volume Name In Description Volume (tr')
In Model Model 1 Drvwell Orywell 2.765E+05 5 Sprayed Sprayed Region of the Containment 4.812E+05 above the Operating Floor at El. 208'10n 6 Unsprayed Unsprayed Reaion of the Containment 6.842E+05 7 Annulus Secondary Containment 1.96E+05 9 Control Control Room 390,020 Room The volume of the Perry control room has recently been re-evaluated. The current volume to be used in Control Room Dose calculations is 390,020 ft3 (DIN 16).
Page 30 8.3.2 Flows From Drywell Volume Into Containment (Suppression Pool Bypass)
The flow rate from the Drywell to the Wetwell are given below, see PSAT 04212H.02 (DIN 43):
TableS-3 Drywall Flows Time After Gap Release Flow from OW to WW Flow from WW to OW (hours) (cfm) (cfm) 0-0.5 0 0 0.5-2.0 3000 0 2.0-720 2.77E+05 2.77E+05 At two hours, the drywell and unsprayed portion of the containment will be assumed to become instantly well-mixed without credit for suppression pool scrubbing in accordance with Regulatory Guide 1.183, Section 3.7 (DIN 7).
From Unsprayed and Sprayed Containment Volumes to the Environment By the time the gap release* begins, the containment is completely isolated and only containment leakage is assumed. The design basis containment leakage for Perry is 0.2% per day. Since the AEGTS will not completely draw down the annulus for 40 seconds, a 40 second po~itive pressure period is assumed in which all containment leakage is assumed to leak directly to the environment, but because there is no radionuclide release during this 40 second time period, before gap release which begins at two minutes, this leakage does not contribute to the onsite or offsite doses and is not included in the model.
From Unsprayed and Sprayed Containment Volumes to the Annulus The majority (89.92%) of the total containment leakage (la) is drawn into the annulus by the AEGTS.
Although the primary containment is enclosed by the secondary containment, there are systems that penetrate both the primary containment and the shield building boundaries that could create potential pathways through which fission products in the primary containment could bypass the leakage collection and filtration systems associated with the shield building. The Perry Technical Specification SR 3.6.1.3.9 (DIN 15) limit the secondary containment bypass leakage to equal to or less than 5.04 percent of the primary containment leak rate. This analysis uses a bypass leakrate of 10.08 percent of the primary containment leak rate. .
From Unsprayed and Sprayed Containment Volumes to the Annulus As stated above, the majority (89.92%) of the total containment leakage (la) is drawn into the annulus where it is filtered by the installed HEPA filters at a credited efficiency of 99% before being released Into the environment.
Page31 Mixing Between the Unsprayed Containment and Sprayed Containment The mixing rate between the unsprayed containment and the sprayed containment is 71,400 cfm, Calculation PSAT 04202U.03, Rev. 0(DIN13).
From Secondary Containment The only flow from secondary containment is via the AEGTS system which draws 2000 cfm through a charcoal-filter unit and HEPA filter unit. The HEPA filters are tested per Regulatory Guide 1.52 and therefore are credited for a 99% removal efficiency in the analysis; however, no credit is taken for the charcoal adsorbers in this analysis.
8.3.3 Removal Mechanisms Natural removal mechanisms for elemental iodine and aerosols will be applied in this calculation using NRC correlations. Elemental iodine removal is credited in the drywell and containment volumes. Aerosol removal is credited only in the drywall and unsprayed region of the containment since containment spray will adversely impact the particle size distribution In the containment.
Fission product removal by containment sprays is considered. The Perry containment spray system is initiated manually based on high radiation readings or is Initiated automatically approximately 10 minutes following a LOCA based on pressure and low water level. In this calculation, sprays are assumed to be manually Initiated at 30 minutes. The Powers model for aerosol removal by sprays which is built into the RADTRAD code Is used in this analysis. Consistent with. the guidance in Section 3.3 of Appendix A to R.G. 1.183, the maximum spray decontamination factors for elemental iodine is 200 based on Standard Review Plan 6.5.2, Section Ill, 0. After the aerosol mass has been depleted by a factor of 50, the spray removal lambda is assumed to decrease by a factor of 10.
The following section determines when these DFs were determined to occur. As discussed In Section 3.3 of Appendix A to R.G. 1.183, these OFs are based on the inventories at the end of the in-vessel release phase. Containment spray is assumed to end at 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> and the aerosol removal by containment spray is terminated.
Decontamination Factor Reductions As discussed above, the elemental iodine removal by natural deposition is neglected after a OF of.200 is reached. Based on the elemental Iodine lambda of 0.878 hf1 in the drywell, a OF of 200 would be reached in approximately six hours without any leakage or decay. The output in Attachment 2 indicates that the Orywell 2-hour post-accident release (I.e., 2.0000 hr) elemental 1-131 inventory of 2.4087E+22 atoms has reduced to 1.29E+20 at 3.0 hours0 days <br />0 hours <br />0 weeks <br />0 months <br /> post-accident representing a OF of 186. This calculation will therefore model the elemental Iodine removal to end at 3.0 hours0 days <br />0 hours <br />0 weeks <br />0 months <br /> in the drywell.
In the containment, the total (sprayed+ unsprayed) elemental 1-131 inventory Is 3.1526E+21 atoms after the drywell is flushed at two hours post-accident (i.e., 2.0000 hr). The total activity in both regions of the
Page 32 containment is considered because, if only the activity in the sprayed region of the containment Yias considered, a longer period of the higher lambdas would be applicable. At 3. 75 hours8.680556e-4 days <br />0.0208 hours <br />1.240079e-4 weeks <br />2.85375e-5 months <br />, the total elemental 1-131 Inventory in the sprayed and unsprayed containment regions is 1.6644E+19 atoms, representing a OF of 189. This calculation will model spray removal to end at 3. 75 hours8.680556e-4 days <br />0.0208 hours <br />1.240079e-4 weeks <br />2.85375e-5 months <br />.
The particulate removal (Powers Model) in the sprayed region of the containment is reduced by a factor of 10 when the aerosol activity is reduced by a OF of 50. In the containment, the total (sprayed +
unsprayed) particulate inventory is 8.13 kg after the drywall is flushed at two hours. At 4.95 hours0.0011 days <br />0.0264 hours <br />1.570767e-4 weeks <br />3.61475e-5 months <br />, the total aerosol inventory Is 1.64E-01 kg, representing a OF of 49.7. This calculation will model this removal coefficient to be reduced at 4.95 hours0.0011 days <br />0.0264 hours <br />1.570767e-4 weeks <br />3.61475e-5 months <br />. This is accomplished t>Y reducing the spray flow used in the Powers Model by a factor of ten at this time.
8.3.4 Release Points All source terms released via containment leakage are released through the plant vent 8.3.5 Model The containment airborne model is illustrated In Figure 2 which is based on the time at which the gap release begins. This figure also includes the MSIV leakage transport pathways.
8.4 Control Room Although the current configuration of the control room HVAC system would automatically Initiate the control room recirculation on a LOCA signal, this analysis assumes that the CRERS is manually initiated at thirty minutes. Once the CRERS is initiated, CRERS fans recycle 27,000 cfm of control room atmosphere through HEPA filters and charcoal adsorbers before being returned to the control room. The normal control room recirculation air flow is 45,000 cfm (DIN 52) including 6,600 cfm of outside air for ventilation. To represent the normal positive pressurization in the control room, the exfiltration air flow is modeled as 4,600 cfm before Isolation at 30 minutes. The RADTRAD code only allows a single control room recirculation air flow. As a result, the normal recirculation air flow Is not modeled. This is acceptable because the normal recirculation flow does not change the radionuclide concentration in the control room.
After Isolation, unfiltered inleakage of 1375 cfm is assumed to be drawn from the control room intake duct for the duration of the postulated accident (30 days). The flow from the control room to the environment is also set at 1375 cfm to avoid pressurization.
Consistent with the requirements of R. G. 1.183, the contribution to the control room dose due to shine from the containment building (0.13 Rem) and release plume (0.002 Rem) must be considered. These dose contributions are given in PSAT 04202H.13 (DIN 17). These 30-day doses to the control room were generated with the previous TIO 14844 source term that assumed an instantaneous release to the containment of 100% of the core Inventory of noble gases and 50% of the radioiodines. These
Page 33 assumptions are conseNative compared to the Alternative Source Term methodology (AST) due to removal of radlolodines from the containment atmosphere by sprays and deposition thereby reducing the radionuclide concentration in containment. In addition, the total halogen release fraction is 0.3 for the
- AST methodology providing additional margin. Based on these considerations, the previously calculated shine and plume doses are considered bounding for this analysis.
8.5 RADTRAD MODEL The models developed for the analysis are illustrated in Figures 1 and 2.
9.0 Operator Actions The operator actions assumed in this analysis include the following:
- 1. Manual initiation of containment spray at 30 minutes
- 2. Manual initiation of CRERS at 30 minutes
- 3. The pH calculation (DIN 26) assumes initiation of Standby Liquid Control (681:6) to control suppression pool pH SL r..
I&.> I. i1*1'1
Page 34 Figure 1 Fission Product Transport Model (ECCS Leakage Pathway) 1- Pool to Environment SUPPRESSION POOL- 1 0.03 2 s ENVIRONMENT - 2 3 24.5-end}
114,379 ft
- 6. 71 cfm (24-24.5 hrs) 2 - Control Room Intake .
6000 cfm + 10% = 6600 cfm 1375 cfm after CRERS initiation 3 - Control Room Exhaust 4800cfm 1375 cfm after CRERS initiation CONTROL ROOM - 3 390,020tt3
Page 35 Figure 2 Fission Product Transport Model (MSIV and Containment Leakage Pathways)
Gap Release Phase 7
- Sprayed lo Sprayed* 5 4.812e5 ft3 6
- Sprayed ID Annulus
.. Environment 3- Unsprayed to Sprayef (4- Sprayed to Unsprll)'ed Annulus-7 9-AEGTS 1.96e5ft3 11.400 c1m I Jl1.400 c:1m (AnruWs to EnvironmenQ ' ~
2000cfm 1-D!ywell to Unsprayed
- - - - - - 3000 cfm Unsprayed. 6
~---.;...i 6.842e5ft3 I: I~----~ lo Annulus 10- CR Intake 2* Unsprayed to 8- Unsprayed lo 6000cfm+10% =6600 cfm Drywell Envfrmunanl 1375 cfm aftllr CRERS inlllallOn after two hours
-. Conlrol Room
- 9 Environment. a 3S0,020ft3 DlyweD-1 2.765e5ft3
- 11-CR Exhaust 4800cfm 1375 cfm after CRERS Initiation MSL2*3 MSL3* 4
~-----;.., 440 ftJ 1-----.i- 292 ft3 12* Drywall to 14-MSL.2 MSL2 L...-----1 to MSL3 16-MSL.3 to Environment MSL1 *2
~--M 146ft3 15
- MSL1 lo Envlmrment 13-0rywell to
~----_.MSL1 L....----i
Page 36 10.0 COMPUTATION The RADTRAD output files, which include the Input summary, are given in Attachments 1 and 2. The*
RADTRAD input and output files used for this calculation are identified below:
Description ECCS Leakage Containment Leakage Plant scenario file PNPP ESF.psf PNPP LOCA.psf Auxiliary RADTRAD Input Files Nuclide Inventory File PNPP ESF.nif PNPP LOCA.nlf Release Fraction and Timing File pnpp_esf.rft PNPP_DBA.rft Dose Conversion Factors Fgr11&12.lnp Fgr11&12.inp Output File PNPP ESF.out PNPP LOCA.out Files for the TSC dose calculation are:
Plant Scenario Flies Output Files PNPP ESF TSC.psf PNPP ESF TSC.out PNPP LOCA TSC.psf PNPP LOCA TSC.out For the TSC analyses, the nuclide inventory files, release fraction and timing files, and the dose conversion factor files for the LOCA and ESF cases are the same as above.
11.0 Overall Results Table 11-1 presents the dose results for individual leakage pathways for MSIV leakage, containment leakage, containment bypass, ECCS leakage, and shine dose. Control room shine dose is from DIN 17 and 25.
Table 11-1 Dose Results (rem TEDE)
Pathway EAB LPZ Control Room TSC Containment & MSIV Leakaae 20.4 5.0 1.7 0.36 ECCS Leakage 0.79 1.83 1.15 0.05 Shine Dose 0.132 0.132*
Total 21.2 6.9 3.0 0.5 Regulatory Limit 25 25 5 5
- Assumed to be the same as the Control Room
CALCULATION ADDENDUM Page 1 0 BV1 I n BV2 l 0 DB I 181 PY TITLE/
SUBJECT:
(MUST MATCH ORIGINAL CALCULATION TITLE (SUBJECT))
Control Rod Drop Accident Radiological Analysis using Alternatllie Source Terms Classification 181 Tier 1 Calculation 181 Safety-Related/Augmented Quality D Nonsafety-Related Open Assumptions? D Yes 181 No . If Yes, Enter Tracking Number Initiating Document (Perry Only) Referenced In Atlas? D Yes 181 No CPerry Onlv> Referenced In USAR Validation Database D Yes 181 No Computer Program(S)
Program Name Version I Revision Category Status Description NIA Originator (Print, Sign & bate)
A. Widmer.A. ~J.'D 6-24-14 Reviewer/Design Verifier(Print, Sign & Date)
Marvin Morris ii\-.:.~\~. 6/2512014 Approver~ s;g jVi. '~(~*.
t>. C.ull ~ r tf//;,~ Lt:JJ2sl I
- r
µ.
.,,D OBJECTIVE OR PURPOSE OFADDENDUM: I The purpose of this addendum is to clarify assumption 3.1.5.8 with respect to the iodine fractions released, and iodine fractions input into the RADTRAD code. One objective is to prevent an error likely situation from occurring during the next revision.
SCOPE OF ADDENDUM:
There is a discrepancy*between Assumption 3.1.5,8 and the inplitinto the RADTRAD code. This addendum is initiated to ensure that the next full revision corrects the discrepancy and to formally document that there is no impact on the results or conclusions.
LIST NEW DOCUMENTS TO BE ADDED TO THE DOCUMENT INDEX (DIN);
8c z
z c:i i5 Document Number/Title Revision, Edition, Date I!!
CD a:
-::J D.
.E 0
D.
D D D D D D
SUMMARY
OF RE SULTS/CONCLUSIONS OF .ADDENDUM:
There are no changes to the results of this calculation. This addendum documents a discrepancy between assumption 3.1,5.8 and the input values into attachments 1, 2, and 3.
The assumption states that the iodine release from the turbine and condenser is assumed to be 97% elemental and 3%
organic and is consistent with guidance In section 3.6 of Appendix C to Regulatory Gulde 1.183 Rev. 0. Attachment 1 (pages 4, 9, 27, and 32) and Attachment 2 (pages 2, 9) used iodine fractions of 95% aerosol, 4.85% elemental, & 0.15% organic. (pages 2; 8) used iodine fractions of 97% elemental and 3% organic. Attachment 3 utilized the correct release from the turbine and condenser as It matches the release fractions contained in assumption 3.1.5.8.
Future revisions of this calculation shall assume the iodine fractions released from the turbine and condenser to be 97%
elemental and 3% organic unless updated regulations dictate othelWise.
As stated above, this inconsistency does not impact the results or conclusions of Revision 1. For the dose associated with the EAB, LPZ, and Control Room (without Isolation), the form of the iodine released does not impact the dose to those areas as no filtration was credited in the calculation for the offsite locations or the Control Room (without isolation). As a result, there Is no change in the consequences for those areas. For the Control Room evaluations which assume Isolation and filtration, there is also no impact on Control Room doses because the efficiencies for the Control Room filtration were set to 80% for both the charcoal and HEPA filters. This ensures that the elemental iodine, organic iodine, and aerosol iodine are filtered the same.
There would be no change to the isolated control room dose unless the filtration efficiencies were changed such that the
CALCULATION ADDENDUM Page2 removal efficiency for different iodine fonns are differeni. As evidence, attachment 2 and attachment 3 of the base calcu!aiion utilized the different iodine fractions. It is noted that the calculated EAB and LPZ doses are identical as seen oii Page 30 of and Page 44 of Attachment ~.
LIMITATIONS OR RESTRICTIONS CREATED BY ADDENDUM:
None IMPACT OF ADDENDUM ON OUTPUT DOCUMENTS:
None DESCRIBE WHERE THE ADDENDUM WILL BE EVALUATED FOR 10CFR50.59 APPLICABILITY:
RAD/SCREEN/EVAL 13-02880 for Revision 1 of this remains applicable.
LIST SUPPORTING DOCUMENTS: (Include total number of pages)
Design Verlfjcatlon Record 1 page Calculation Review Cttecklist 3 pages Design Interface Summary 7 pages LIST ATTACHMENTS: (Include total number of pages)
None
3.2 CLASSIFICATION OF STRUCTURES, COMPONENTS AND SYSTEMS Certain structures, components and systems of the nuclear plant are considered important to safety because they perform safety actions required to avoid or mitigate the consequences of abnormal operational transients or accidents. The purpose of this section is to classify structures, components and systems according to the importance of the safety function they perform. In addition, design requirements are placed upon such equipment to assure the proper performance of safety actions, when required.
3.2.1 SEISMIC CLASSIFICATION Plant structures, systems and components important to safety are designed to withstand the effects of a Safe Shutdown Earthquake (SSE) and remain functional if they are necessary to assure:
- a. The integrity of the reactor coolant pressure boundary,
- b. The capability to shut down the reactor and maintain it in a safe condition, or
- c. The capability to prevent or mitigate the consequences of accidents that could result in potential offsite exposures comparable to the guideline exposures of <10 CFR 100>.
Plant structures, systems and components (including their foundations and supports) designed to the event of an SSE are designated as in
. Structures, components, designated as Safety Class 1, Safety Class 2 or Safety e <Section 3.2.3> for a discussion of safety classes) are Category I except for (1) those noted in- a. Demisters to remove large particles and water droplets (about 1 micron diameter) .
- b. Roughing filters to remove large particles (about 1 micron).
- e. Gasketless activated charcoal adsorber beds to remove gaseous elemental and organic iodines.
- f. HEPA filters downstream of the charcoal beds to remove charcoal particles that may be entrained in the air stream.
- g. A fan external to the plenum.
- h. Instrumentation.
- i. Test ports.
- j. Water deluge system for fire protection.
- a. The containment spray system (CSS) is a part of the residual heat removal (RHR) system. *
- b. The CSS provides containment cooling following a loss-of-coolant accident, in addition to being a fission product removal mechanism.
- c. The CSS consists of two completely redundant and independent loops.
- d. The CSS is designed to remain operable in the containment accident environment, which is discussed in <Section 3.11>.
- 6. 5-11 January, 2003
- .-r~ M.08..a-\
- ~ ~pf"'~~s ~.... ~:S->~e.A. ~ ~._f~~
- postaccident.
5.5 REFERENCES
FOR SECTION 6.5
- 1. Postma, A. K.; Sherry, R. R.; Tarn, P. S.; "Technological Bases for Models of Spray Washout of Airborne *Contaminants in Containment Vessels," <NUREG/CR-0009>, October 1978.
- 2. ANSI/ANS-56.3-1979, "American National Standard for PWR and BWR Containment Spray System Design Criteria."
- 3. Electrical Power Research Institute, "Generic Framework for Application of Revised Accident Source Terms to Operating Plants,"
TR-105909, Interim Report, November, 1995.
4.... PeJ:estaF Applieel TeeR.ReleEjy, !Re,, "STAAWAY:A, A Geele fe;r; EvalYatiR(j .
Se J'eEe AeeieleRt Ae;r;esel 8eeav=ie;r; iR WaeleaF Peue: PJ:aat 1
GeRtaiRR\8Rts1 A Geae QessriptieR aaa ValiaatieR aRa VeFifieakieR
- 4. Regulatory Guide 1.52, "Design, Inspection, and Testing Criteria for Air Fiitration and Adsorption Units of Post-Accident Engineered-Safety-Feature Atmosphere Cleanup Systems In LlghtWater-Cooled Nuclear Power Plants",. Revision 2, March 1978.
- 5. NUREG-0800, "Standard Review Plan (SRP) 6.5.2, Containment Spray As A Fission Product Cleanup System," Revision 4, March 2007.
- 6. Calculation 3.2.15.16, "Design Basis LOCA Dose Evaluation Using Alternate Source Terms," Revision O Oeteber 20ts.
Revision 12 6.5-24 January, 2003
TABLE 6.5-9 INPUT PARAMETERS FOR THE SPRAY REMOVAL ANALYSIS 481174 Unsprayed containment volume, F3 684226 Mean spray fall height, ft Number of spray pumps operating 1 Spray flow rate, gpm *5, 250 Spray solution pH 7.0 Q, Spray Flux, cfm/ft2 0.0621 Alpha, unsprayed/sprayed volume 1.422 Pct, uncertainty percentile 10 Geemetrie meaR Elrep siae fer spatial ElietrisYtiea 1 em Geemetrie meaR partiele eiae fer iaeemiR§ ae;eesel 1 em Geemet;eie meaR staRElare eeviatieR Ne uall eeR9easatieR Ne eeaEieRsatieR eR HateE Elreplete Ne eeaE;:i.Ele;eatieR ef pailtiele &ly§reseepieity Revision 12 6.5-56 January, 2003
TABLE 15.0-4.
DOSE CONVERSION FACTORS 111 Thyroid Whole Body Isotope (rem/Ci) 0.25xMeV/dis I-131 1. 49E+6 8. 72E-2 I-132 5.35E+4 5.13E-1 I-133 3.97E+5 1.55E-1 I-134 2.54E+4 5.32E-l I-135 1.24E+5 4.21E-1 Kr-83m 5.02E-6 Kr-85 3. 72E-2 Kr-85m 5.25E-4 Kr-87 1. 87E-l Kr-BB 4.64E-1 Kr-89 5.25E-1 Xe-13lm 2.92E-3 Xe-133m 8.00E-3 Xe-133 9.33E-3 Xe-135m 9.92E-2 Xe-135 5.72E-2 Xe-137 4.53E-2 Xe-138 2.BlE-1 Breathing Rates Time Period (hr) 0-8 8-24 24-720 NOTES: CRDA, MSLB 111 The lowing dose conversion factors (DCF's) are used in the alternative term analyses; 1989
~ - QCF's fer iAAalatiea:
(Reference r"'!""'!~~~~-=-....,...~~~~~=-~....,...~--.,.,,..,,...,,...-:~~.._~~:""t
~FHA - CEDE: EPA Federal Guidance Report 11 - 1989 (Reference 11)
DOE/EDE: MACCS2 computer code (Reference 12), which used Federal Guidance Report 12 - 1993 (Reference 13).
121 This breathing rate was used for the duration of the Control Room radiological consequence analyses.
Revision 13 15.0-37 December, 2003
. TABLE 15.4-12 CONTROL ROD DROP ACCIDENT EVALUATION PAR.1\M&TERS Scenario 1 Scenario 2 Assumptions Assumptions I. Data and assumptions used to 1376 estimate radioactive source from postulated accidents.
A. Power level 3,833 MWt B. Burnup N/A
- c. Fuel damaged *~ rods.ut D. Release of activity by nuclide
(1) Organic ~ ~ ----------:~~0.15
~ 4.85
( 2) Elemental ~ ~ 95 (3) Particulate ~ ~
F. Reactor coolant activity before the accident. N/A N/A II. Data and assumptions used to estimate activity released.
A. Condenser leak rate (%/day) 1.0 N/A B. Turbine building leak rate (%/day) N/A
- c. Valve closure time (sec) N/A D. Adsorption and filtration
- efficiencies (1) Organic iodine N/A N/A (2) Elemental iodine N/A N/A (3) Particulate iodine N/A N/A (4) Particulate fission products N/A N/A E. Recirculation system parameters (1) Flow rate N/A N/A (2) Mixing efficiency N/A N/A (3) Filter efficiency N/A N/A F. Containment spray parameters (flow rate, drop size, etc.) N/A N/A G. Containment volumes N/A N/A Revision 12 15.4-44 January, 2003
The RAST _analysis 'e13 9 p 11 rs 11 ed initially t 0 s 11 pp 0 rt an jncrease in the main steam line leak rate to 250 scfh and to eliminate the MSIV leakage Control System
-~
The ~analysis is based on the following: Regulatory Gulde 1.183 0
- controlling the pH of the water in the containment to prevent iodine re-evolution,
- operating the containment spray system for up to 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />
<Section 6.5.2.3>,
- not crediting iodine removal by charcoal adsorbers in the Annulus Exhaust Gas Treatment System (AEGTS),
- delaying actuation of the control room emergency recirculation utillzlnQ.----~ for up to 30 minutes, c.e~:ea.s.i..n..g elemental and organic iodine removal efficiencies of~80percentforthel control room emergency recirculation system charcoal adsorbers lutlllzingan~m 9 5 percent to 50 percent,
.
- increasing the engineered safety feature system leakage outside The SA.S.:r. analysis considers the following four potential fission product release pathways following the design basis LOCA:
- main steam isolation valve leakage,
- containment leakage, Revision 12 15.6-23 January, 2003
The analysis conservatively assumes that the fission product leakage from the main steam lines is released directly into the environment.
The leakage past the MSIVs is conservatively assumed to begin immediately after the accident. In actuality, the three intact steam lines would contain trapped steam which would be relatively cooler and more dense a*s compared to the atmosphere in the reactor vessel upper head during the overheating of the core. This condition would greatly inhibit mixing between the activity released from the core and the steam leaking through the three intact steam lines and the three*associated sets of MSIVs. However, for conservatism, all of the lines are assumed to be leaking contaminated drywell atmosphere.
Other significant conservatisms in the analysis of steam line transport include:
S't"E.'T" i:N..~~'-"ri-'> ~~ 111.c\A...~ k~~n'-~tr\~ ... 0 (1) consd<eratiat pf rt11ced~team lipe mass leak rate with t 'I\ -&, ro,,:J D" \.:e::l:~ *tM.,.. t~bod 011.t~anL C'\$l 'Is (no r~a'\ Ct'\. -flow
,.;,,-.~~$
(2)
~O~M.
l'"-AJ.J.J.J.Jo..A.Jo..AAAAA>.J.,,A.>..llJ..-.......,,_,.....,,_,-.;-.;..__,...__...__,...__,......._......._.~..A..A..A..A.AJ>o_,,_-'! of *~
(V\A.l{\
No consideration of particulate removal and even plugging of the 5*~
extremely small MSIV leak paths due to particulate deposition at tr N&-s.) >j the entrance to or within the leak path as the gas flow Two configurations were analyzed to cover all single-failure possibilities. In the first configuration (Configuration 1), the inboard MSIV on the affected line was assumed to fail open, and this line was assumed to leak at 100 scfh. The three intact lines were then assumed to leak at 100 scfh, 50 scfh, and 0 scfh to maximize flow rates through the lines, which in turn maximizes the activity release. At 20 minutes after the start of release the third safety-related and seismically-qualified isolation valves (just outboard of the outboard Revision 12 15.6-25 January, 2003
\
~O-IV\
Elemental iodine retention efficiency is based on resuspension rates from (Reference the main steam lines to retain aerosol fission products) was slightly reduced in the analysis. This aerosol removal efficiency is equivalent to an increase in aerosol penetration of 10 percent. This was done to further increase steam line pathway.
, 5h"A.\ \v -ti> ~ ~D.\o,G.o\ ~~\ ct...f*~~e.('c:.."( r(l...&..w..-\loV\.J -t\.-e...
- 15. 6. 5. 5 .1. 2 Fission Product Transport in Drywell .e,.~l t oA1 V\.Q.-o ('Q..---\e.t'\.""OI\
~ ~ ~(._j WC'-' ~So rQ.bcacl_
The most limiting OBA, with respect to the offsite and control room b~ \O°b .for radiological consequences, is considered a large-break LOCA ~~t\S:r\\)
of a double guillotine pipe rupture in one of the four main steam lines "\-D** '\ 5~.
upstream of the inboard MSIV. It is further conservatively assumed that all fission products are released directly to the drywell and leaked into the primary containment and into the main steam lines, bypassing the suppression pool. The analysis also assumes that at a point two hours after accident initiation (when the ECCS is assumed to be able to reach the core and reflood it) the fission products are homogeneously distributed between the drywell and the primary containment. The objective of this well mixed approach is to achieve an appropriate balance for the design of drywell leakage mitigative devices such as the MSIVs as well as containment leakage mitigative features such as the+-~-
annulus exhaust gas treatment system. Reference HEPA filters In the 19 in-vessel fission product releases terminate 2 hours2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br /> after accident initiation. For the fission product releases to terminate, the reactor vessel would need to be reflooded. In lieu of evaluating all of the potential steaming rates due to various reflooding scenarios, the analysis assumes that a substantial amount of fission products will end up in the primary containment as well as in the drywell, and as such, Revision 12 15.6-27 January, 2003
1exr*t 1 mltigati ve features such as the HEPA filters in the annulus effl 11ent gas treatment system are designed to acconunodate a significant portion of the source term. The 2-hour assumption for the homogeneous mixture of the source term between the drywell and the containment is used since it provides an appropriate balance, because the "worst 2 hours2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br />" are considered for the EAB radiological dose results, as opposed to simply the first 2 hours2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br /> as was done when the TIO source term was used.
The radiological consequences are dependent upon the drywell bypass leakage prior to the termination of fission product release at 2 hours2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br />.
Because of this sensitivity, the analysis uses a steaming rate of an intact core without relocation to the lower head region, on the order of 3,000 cfm. For the period prior to 2 hours2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br />, the analysis conservatively does not credit steaming due to relocation, cooling from alternative water sources, or the release of hydrogen gas, all of which would provide a higher steaming rate and remove more of the fission products from the drywell region.
--~:------~~~~---...
~e.t"tiJ J:o~~Nl,.... ~J.
Aeroso Deposition r.I.:itbi n ~he B!!}Well Cl Activity released to the drywell as a result of the design basis loss-of-coolant-accident ls initially airborne and can be removed from the atmosphere in one of four ways:
(1) Convection from the drywell to the containment (2) Natural removal within the drywell (e.g., particulate sedimentation)
(3) Leakage into the broken steam line and through the MSIVs (4) Leakage back into the reactor vessel and through the MSIVs Revision 12 15.6-28 January, 2003
Elemental Iodine moval Is credlte In the drywall volu lrbome element.al lodloe la removed by deposition to the waflso . This process Is driven by the tempe re differences elween the surfaces and the atmosphere. The cafcutated retoval constants are applied untll a decontamlnaUon faotori {OF) of 00 has been obtained. Aerosol removal
- In th rywel s modeled using the Powe,as removal model as given In l:t-6189 (Reference 20). The lower *
. bo <fecon amlnatlon coemctent associated with the 1oth ercentlle uncertainty Wb used for conservatism.
- The leakage cont rt hut! on is sm~ll by .design/ and therefor pri cipal ~echanisms for depletio of activity in the drywall tmosphere (ot er. . by radioactive decay) is convection from the drywall than con ainment and natural removal w thi~ the drywall.
de letlon due to MSIV Following the fuel releas'! phase ~he accident, the restoration of ECCS (thus arresting further core damage) would quench the core debris, and results in a rapid sweep-out f the drywall into the containment as discussed in Section 5.2.3 of (Re erence 18).
For the design basis analysis, a egotiated licensing basis was established for the transport of cti.vity between the containment and the drywall. The negotiated basi in effect mixes activity between the regions and does not consider a s eep-out of the activity after two hours. The negotiated parame- &;~:s-eea&~at; for the (30 days). reduces at 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> as permitted by
- 2. ~ h.out93 Although the primary containment is enclosed by the secondary containment, there are systems that penetrate both the primary Revision 12 15.6-30 January, 2003
- 15. 6. 5. 5 .1. 9 Control Room Habitability Upon receipt of an ESF actuation system signal or high radiation, the control room Heating, Ventilation, and Air Conditioning (HVAC) system is designed to automatically switch to the emergency recirculation mode of operation (CRERS). The analysis conservatively assumes a 30-minute delay in actuation of the CRERS.
6.7 REFERENCES
FOR SECTION 15.6
- 1. Moody, F. J., "Maximum Two-Phase Vessel Slowdown From Pipes," ASME Paper Number 65-WA/HT-1, March 15, 1965.
Revision 14 15.6-43a October, 2005
TABLE 15.6-12a LOSS-OF-COOLANT ACCIDENT PARAMETERS AND ASSUMPTIONS USED IN RADIOLOGICAL CONSEQUENCE CALCULATIONS MAIN STEAM ISOLATION VALVE LEAKAGE PATHWAY Parometor ~ ~
Reactor power (315'~ f"t04:, )(I ,0.2.) .3.15.B. MWt ~
Drywell volume 2.765 K 105 t 3 6
~~ldelJ. volume 1.165 x 1 t Volume of one main steam line between MSIV's 146 ft 3
]lnlnmetr1c flow rate, drywel 1 to al 1 m3jn steam ljnes (total leakage) 29Q cfb frrng t - a to t e 7484 seconds 247 cfh frrnn t = 1484 seconds to 30 days JlQJ umptri C fl Clef rate (m3yimnm) d QDp main steam 1 i ne t*n pny1 roumpgt 191 cfm
.__---iVolumetrlc flow rate, drywall to broken steam line Oto 7484 seconds 1.987 ft3/mln 7484 seconds to 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> 1.647 ft3/min 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> to 30 days 1.371 ft3/mln Volumetric flow rate, drywall to Intact steam lines Oto 7484 seconds 2.98 ft3/mln 7484 seconds to 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> 2.47 ft3/mln 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> to 30 days 2.056 ft3/min V ""~t-ri c.. f la~ ra.t.e.-( l"l ~}(.~ mu.~) it'\ 3 .. l~ 3 { f:?'jrr.. i I\
111 \
Dt\Q... (fl.~\" s\.~m. \CV\.4.. 1 ba..:\w~ ~
\ .
l'l\S \V .s J ~ -io ~V1f'o~~*'*t,
'\: ..: o to ,30 >.."&-.~S Vo\~'-' .etu~ fi,..\-(!.... i~ i~~t..T M.bd" &.\, 115 ~f:.)/('\tt\
->*e..&.~ h~s.., ~~~ ~ iY\S.\"'.s)
~ ~ O-V'"1ro~~--\-, t "" 0 tu 30 A.~ S Revision 12 15.6-58 January, 2003
TABLE 15.6-12b LOSS-OF-COOLANT ACCIDENT PARAMETERS AND ASSUMPTIONS USED IN RADIOLOGICAL CONSEQUENCE CALCULATIONS CONTAINMENT LEAKAGE PATHWAY Value 00 ft
~x 0 ft 3 /min 2 hours2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br /> - 3 days ~ x 10 5 ft 3 /min Flow rate between rywell and region 0 ft 3 /min Flow rate from rayed region unsprayed region 71,400 ft 3 /min Flow rate from nsprayed region to sprayed region 71, 400 ft 3 /min Containment leak rate to environment
~
from sprayed regio~a_.....
0- 49 89Q9RQ~ _
- o. 067 ft /mi~ o"f (;2. ft-S/
[!QJ.q ..g,,g. percent -........... 0
~ (""tr\
uncertainty*
~ ....._ distribution Spray fall height ~~ft Spray removal rate for elemental iodine